Cationic diazo compound, compositions comprising at least one cationic diazo compound as a direct dye, a process for dyeing keratin fibers and device therefore

ABSTRACT

The present disclosure relates to a cationic diazo compound of formula (I): 
 
Dye1-LK-Dye2 
 
wherein Dye1 and Dye2 are such that the compound of formula (I) is not symmetrical, and are chosen from:  
                 
The disclosure also relates to dye compositions comprising compounds of fomrula (I) as direct dye, and further relates to a process for dyeing keratin fibers using the compositions disclosed herein and also to a multi-compartment device.

This application claims benefit of U.S. Provisional Application No.60/588,041, filed Jul. 15, 2004, the contents of which are incorporatedherein by reference. This application also claims benefit of priorityunder 35 U.S.C. § 119 to French Patent Application No. 04 06871, filedJun. 23, 2004, the contents of which are also incorporated by reference.

The present disclosure relates to a cationic diazo compound, to dyecompositions comprising at least one cationic diazo compound as directdye in a medium that is suitable for dyeing keratin fibers, and also toa process for dyeing keratin fibers using at least one compositioncomprising at least one cationic diazo compound and a multi-compartmentdevice.

It is known practice to dye keratin fibers, for example, human keratinfibers such as the hair, with dye compositions comprising direct dyes.These compounds are colored and coloring molecules with affinity for thefibers. It is known practice, for example, to use direct dyes of thenitrobenzene type, anthraquinone dyes, nitropyridines and dyes of theazo, xanthene, acridine, azine or triarylmethane type.

These dyes are usually applied to the fibers, optionally in the presenceof an oxidizing agent, if it is desired, to obtain simultaneouslightening of the fibers. Once the leave-in time has elapsed, the fibersare rinsed, optionally washed and dried.

The colorations resulting from the use of direct dyes are temporary orsemi-permanent colorations since the nature of the interactions thatbind the direct dyes to the keratin fiber, and their desorption from thesurface and/or the core of the fiber, are responsible for their poordyeing power and their poor relative resistance to washing or toperspiration.

An additional difficulty also arises, associated with the fact that inorder to obtain a desired color, it is necessary in most if not allcases to mix together several dyes. However, each dye does not have thesame affinity for the fibers, which is reflected either by heterogeneouscolorations or by changes in color over time, for example after washingthe fibers at least one time, exposure to sunlight, etc.

Disclosed herein in one embodiment are direct dyes that do not have thedrawbacks of the existing direct dyes.

Disclosed herein in one embodiment are direct dyes with which variedshades may be obtained without the problem of changes in color overtime.

Also, disclosed herein in one embodiment is a cationic diazo compound offormula (I):Dye1-LK-Dye2   (I)or the addition salts thereof with an acid, the electrical neutrality ofthe compounds is ensured by at least one cosmetically acceptable anionAn, wherein:

Dye1 and Dye2 are such that the compound of formula (I) is notsymmetrical, and are chosen from:

wherein:

W₁ and W₆, which may be identical or different, are each chosen from—NR₁— and —O—, wherein R1 is chosen from a hydrogen atom, and saturatedand unsaturated, aromatic and non-aromatic, optionally substitutedC₁-C₂₀, for example, C₁-C₁₆, hydrocarbon-based chains, which may form atleast one optionally substituted 3- to 7-membered carbon-based ring,optionally interrupted with at least one hetero atom or with at leastone group bearing at least one hetero atom, for example, chosen fromoxygen and nitrogen;

wherein R₁ may form with all or part of the group LK and with thenitrogen atom to which each is attached at least one cationic andnon-cationic, saturated and unsaturated, aromatic and non-aromatic,optionally substituted 5- to 7-membered heterocycle;

W′₁ and W′₆, which may be identical or different, are each chosen fromgroup —NR′₁R′₂ or —OR′₃, wherein R′₁, R′₂ and R′₃, which may beidentical or different, are each chosen from a hydrogen atom andsaturated and unsaturated, aromatic and non-aromatic, optionallysubstituted C₁-C₂₀, for example, C₁-C₁₆, hydrocarbon-based chains, whichmay form at least one optionally substituted 3- to 7-memberedcarbon-based ring, optionally interrupted with at least one hetero atomor with at least one group bearing at least one hetero atom, forexample, chosen from oxygen and nitrogen; R′₁ and R′₂ optionallyforming, with the nitrogen atom to which they are attached, anoptionally substituted 5- or 7-membered heterocycle optionallycomprising another nitrogen or non-nitrogen hetero atom;

wherein R′₁, R′₂ or R′₃ may form, with all or part of the group LK andwith the nitrogen or oxygen atom to which each is attached, cationic andnon-cationic, saturated and unsaturated, aromatic and non-aromatic,optionally substituted 5- to 7-membered heterocycles;

W₂, W₅, W′₂ and W′₅, which may be identical or different, are eachchosen from:

wherein:

-   -   X₁ is chosen from a nitrogen atom or CR₇;    -   X₂ is chosen from a nitrogen atom or CR₈;    -   Z, is chosen from a nitrogen atom or CR₁₀;    -   Z₂ is chosen from a nitrogen atom or CR₁₁;    -   R₄, R₅; R₆, R′₆, R₇, R₈, R₁₀ and R₁₁, which may be identical or        different, are chosen from:        -   a hydrogen atom        -   linear and branched, saturated and unsaturated, aromatic and            non-aromatic, optionally substituted C₁-C₁₆            hydrocarbon-based chain, which may form at least one            optionally substituted 3- to 6-membered carbon-based rings,            optionally interrupted with at least one hetero atom or with            at least one group bearing at least one hetero atom, for            example, chosen from oxygen and nitrogen;        -   a hydroxyl group,        -   a C₁-C₄ alkoxy group, a C₂-C₄ (poly)hydroxyalkoxy group; an            alkoxycarbonyl group (RO—CO—) wherein R is chosen from a            C₁-C₄ alkyl radical, and an alkylcarbonyloxy radical            (RCO—O—) wherein R is chosen from a C₁-C₄ alkyl radical;        -   an amino group, an amino group substituted with at least one            C₁-C₄ alkyl radical, which may be identical or different,            optionally bearing at least one hydroxyl group, the two            alkyl radicals optionally forming, with the nitrogen atom to            which they are attached, a 5- or 6-membered heterocycle            optionally bearing another nitrogen or non-nitrogen hetero            atom; an alkylcarbonylamino group (RCO—NR—) wherein R, which            may be identical or different, are each chosen from C₁-C₄            alkyl radicals; a carbamoyl group ((R)₂N—CO) wherein R,            which may be identical or different, are chosen from, a            hydrogen atom and a C₁-C₄ alkyl radical; a ureido group            (N(R)₂—CO—NR′—) wherein R and R′, which may be identical or            different, are each chosen from a hydrogen atom and a C₁-C₄            alkyl radical; a sulfonamide group ((R)₂N—SO₂—) wherein R,            which may be identical or different, are each chosen from a            hydrogen atom and a C₁-C₄ alkyl radical; an            alkylsulfonylamino group (RSO₂—NR′—) wherein R and R′, which            may be identical or different, are each chosen from a            hydrogen atom and a C₁-C₄ alkyl radical; a guanidinium group            ((R′)₂N—C(═NH₂ ⁺)—NR—) wherein R and R′, which may be            identical or different, are each chosen from a hydrogen atom            and a C₁-C₄ alkyl radical;        -   a nitro group; a cyano group; a halogen atom, for example,            chlorine or fluorine;        -   R₄, R₅, R₆, R′₆, R₇, R₈, R₁₀ and R₁₁, which may be identical            or different, may optionally form, with all or some of the            groups W′₁ or W′₆, a saturated and unsaturated, aromatic and            non-aromatic, optionally substituted 5- to 7-membered            heterocycles;        -   a bond from W′₂ to W′₁ or to the group LK, or from W′₅ to            W′₆ or to the group LK;        -   a is the bond from W₂, W₅, W′₂ or W′₅ to the azo group            —N═N—;        -   b is the bond from W₂ to W₁, from W₅ to W₆, from W′₂ to W′₁            or to the group LK, or from W′₅ to W′₆ or to the group LK;    -   R₉ is chosen from:        -   a hydrogen atom,        -   linear and branched, saturated and unsaturated, aromatic and            non-aromatic, optionally substituted C₁-C₁₆            hydrocarbon-based chain, which may form at least one            optionally substituted 3- to 7-membered carbon-based ring,    -   n and n′ are chosen from integers and their sum is less than or        equal to 6;

W₃ and W₄, which may be identical or different, are each chosen fromcationic heteroaromatic radicals chosen from:

-   -   wherein R′₄, which may be identical or different, are chosen        from:        -   linear and branched, saturated and unsaturated, aromatic and            non-aromatic, optionally substituted C₁-C₁₆            hydrocarbon-based chains, which may form at least one 3- to            6-membered carbon-based ring, optionally interrupted with at            least one hetero atom or with at least one group bearing at            least one hetero atom, for example, chosen from oxygen and            nitrogen;        -   a hydroxyl group,        -   a C₁-C₄ alkoxy group, a C₂-C₄ (poly)hydroxyalkoxy group; an            alkoxycarbonyl group (RO—CO—) wherein R is chosen from a            C₁-C₄ alkyl radical, and an alkylcarbonyloxy radical            (RCO—O—) wherein R is chosen from a C₁-C₄ alkyl radical;        -   an amino group, an amino group substituted with at least one            C₁-C₄ alkyl radical, which may be identical or different,            optionally bearing at least one hydroxyl group, the two            alkyl radicals optionally forming, with the nitrogen atom to            which they are attached, a 5- or 6-membered heterocycle            optionally bearing another nitrogen or non-nitrogen hetero            atom; an alkylcarbonylamino group (RCO—NR′—) wherein R is            chosen from a C₁-C₄ alkyl radical and R′ is chosen from a            hydrogen and a C₁-C₄ alkyl radical; a carbamoyl group            ((R)₂N—CO—) wherein R, which may be identical or different,            are chosen from a hydrogen atom and a C₁-C₄ alkyl radical; a            ureido group (N(R)₂—CO—NR′—) wherein R and R′, which may be            identical or different, are each chosen from a hydrogen atom            arid a C₁-C₄ alkyl radical; a sulfonamide group ((R)₂N—SO₂—)            wherein R, which may be identical or different, are each            chosen from a hydrogen atom and a C₁-C₄ alkyl radical; an            alkylsulfonylamino group (RSO₂—NR′—) wherein R and R′, which            may be identical or different, are each chosen from a            hydrogen atom and a C₁-C₄ alkyl radical; a guanidinium group            ((R′)₂N—C(═NH₂ ⁺)—NR—) wherein R and R′, which may be            identical or different, are each chosen from a hydrogen atom            and a C₁-C₄ alkyl radical;        -   a nitro group; a cyano group; a halogen atom, for example,            chlorine or fluorine;        -   wherein two radicals R′₄ borne by two adjacent carbon atoms            of a main ring may optionally form an aromatic or            non-aromatic, 5- or 6-membered secondary-ring, optionally            substituted with at least one group chosen from a hydrogen            atom; hydroxyl groups; C₁-C₄ alkyl radicals; C₁-C₄ alkoxy            radicals; C₂-C₄(poly)hydroxyalkoxy radicals; amino radicals;            amino radicals substituted with at least one C₁-C₄ alkyl            radicals, which may be identical or different, optionally            bearing at least one hydroxyl group; for example, the            secondary ring is a 6-membered aromatic ring optionally            substituted as disclosed above;    -   R′₅ is chosen from linear and branched, saturated and        unsaturated, aromatic and non-aromatic, optionally substituted        C₁-C₁₆ hydrocarbon-based chains, which may form at least one        optionally substituted 3- to 6-membered carbon-based ring,        optionally interrupted with at least one hetero atom or with at        least one group bearing at least one hetero atom, for example,        chosen from oxygen, nitrogen and sulfur; wherein R′₅ is such        that the atom directly linked to the quaternized nitrogen atom        is a carbon atom;    -   R′₇ is chosen-from an optionally substituted C₁-C₄ alkyl        radical; an optionally substituted phenyl radical; and an        optionally substituted benzyl radical;    -   the bond c links the cationic radical defined by formulae (1)        to (11) to the azo group; wherein said bond may be on the main        or secondary ring; for example, the bond c with the azo group is        on the main ring;    -   p is an number ranging from 0 to 4, p′ is an number ranging from        0 to 2 and p″ is an number ranging from 0 to 3;    -   wherein, if the main ring does not bear the maximum number of        substituents, then the unsubstituted position(s) bear(s) a        nitrogen atom;

LK is chosen from saturated and unsaturated, linear and branched, cyclicand non-cyclic, aromatic and non-aromatic, optionally substitutedC₂-C₄₀, for example, C₂-C₂₀ hydrocarbon-based chains, bearing at leastone cationic charge, optionally interrupted with at least one heteroatom or group comprising at least one hetero atom, for example, oxygenor nitrogen;

-   -   wherein, LK may end with a hetero atom or group bearing at least        one hetero atom, for example, oxygen or nitrogen, if LK is        linked to W′₂ or W′₅; and    -   wherein LK may end with a group bearing at least one hetero atom        chosen from —CO— and —SO₂— if LK is linked to W₆ or W₁;

Another embodiment is a dye compositions comprising, in a medium that issuitable for dyeing keratin fibers, at least one compound of formula(I):Dye1-LK-Dye2   (I)or the addition salts thereof with an acid, the electrical neutrality ofthe compounds is ensured by at least one cosmetically acceptable anionAn, wherein Dye1, LK and Dye2 are as defined above.

Another embodiment is a process for dyeing keratin fibers comprisingplacing at least one composition comprising, in a medium that issuitable for dyeing keratin fibers, at least one compound of formula(I):Dye1-LK-Dye2   (I)or the addition salts thereof with an acid, the electrical neutrality ofthe compounds is ensured by at least one cosmetically acceptable anionAn, wherein Dye1, LK and Dye2 are as defined above, in contact with thewet or dry fibers, for a time that is sufficient to obtain the desiredeffect.

Another embodiment is a multi-compartment device comprising, at leastone compartment, at least one composition comprising, in a medium thatis suitable for dyeing keratin fibers, at least one compound of formula(I):Dye1-LK-Dye2   (I)or the addition salts thereof with an acid, the electrical neutrality ofthe compounds is ensured by at least one cosmetically acceptable anionAn, wherein Dye1, LK and Dye2 are as defined above, and at least onecompartment comprising an oxidizing composition.

In an embodiment compounds of formula (I):Dye1-LK-Dye2   (I)or the addition salts thereof with an acid, the electrical neutrality ofthe compounds is ensured by at least one cosmetically acceptable anionAn, wherein Dye1, LK and Dye2 are as defined above, have at least oneproperty chosen from good fastness with respect to external agents suchas, for example, shampoos, even when the keratin fiber is sensitized;access to colorations that are less chromatic than those obtained withsymmetrical compounds.

Other characteristics, aspects, subjects and advantages of the presentdisclosure will emerge even more clearly on reading the description andthe concrete, but non-limiting, examples that follow.

For example, keratin fibers may be chosen from human keratin fibers, forexample, the hair.

In an embodiment, Dye1 and Dye2 are such that the compound of formula(I) is not symmetrical; in other words, there is no axis or plane ofsymmetry passing through LK, said axis or plane of symmetry iscoincident with or perpendicular to the main chain of LK.

As used herein:

-   -   an alkyl radical is linear and branched,    -   an alkyl radical or the alkyl part of a radical may be        substituted with at least one substituent chosen from:        -   hydroxyl,        -   C₁-C₄ alkoxy, C₂-C₄ (poly)hydroxyalkoxy,        -   amino, amino substituted with at least one C₁-C₄ alkyl            group, which may be identical or different, optionally            bearing at least one hydroxyl group, said alkyl radicals            optionally forming, with the nitrogen to which they are            attached, a 5- or 6-membered heterocycle optionally            comprising at least one other nitrogen or non-nitrogen            hetero atom,    -   an aryl or heteroaryl radical or the aryl or heteroaryl part of        a radical may be substituted,at a carbon atom with at least one        substituent chosen from:        -   a C₁-C₁₆, for example, C₁-C₈ alkyl radical, optionally            substituted with at least one radical chosen from hydroxyl,            C₁-C₂ alkoxy, C₂-C₄ (poly)hydroxyalkoxy, acylamino, amino            substituted with two identical or different C₁-C₄ alkyl            radicals, optionally bearing at least- one hydroxyl group,            or the two radicals optionally forming, with the nitrogen            atom to which they are attached, a 5- to 7-membered, for            example, 5- or 6-membered, heterocycle, optionally            comprising another nitrogen or non-nitrogen hetero atom;        -   a halogen atom such as chlorine, fluorine or bromine;        -   a hydroxyl group;        -   a C₁-C₂ alkoxy radical; a C₂-C₄ (poly)hydroxyalkoxy radical;        -   an amino radical; an amino radical substituted with at least            one C₁-C₄ alkyl radicals, which may be identical or            different, optionally bearing at least one hydroxyl group,            or amino with two optionally substituted C₁-C₂ alkyl            radicals;        -   an acylamino radical (—NR—COR′) wherein R is chosen from a            hydrogen atom and a C₁-C₄ alkyl radical optionally bearing            at least one hydroxyl group and R′ is chosen from a C₁-C₂            alkyl radical; a carbamoyl radical ((R)₂N—CO—) wherein R,            which may be identical or different, are each chosen from a            hydrogen atom and a C₁-C₄ alkyl radical optionally bearing            at least one hydroxyl group; an alkylsulfonylamino radical            (R′SO₂—NR—) wherein R is chosen from a hydrogen atom and a            C₁-C₄ alkyl radical optionally bearing at least one hydroxyl            group and R′ is chosen from a C₁-C₄ alkyl radical and a            phenyl radical; an aminosulfonyl radical ((R)₂N—SO₂—)            wherein R, which may be identical or different, are each            chosen from a hydrogen atom and a C₁-C₄ alkyl radical            optionally bearing at least one hydroxyl group,    -   the cyclic or heterocyclic part of a non-aromatic radical may be        substituted at a carbon atom with at least one substituent        chosen from:        -   hydroxyl,        -   C₁-C₄ alkoxy, C₂-C₄ (poly)hydroxyalkoxy,        -   alkylcarbonylamino((RCO—NR′—) wherein R′ is chosen from a            hydrogen atom and-a C₁-C₄ alkyl radical optionally bearing            at least one hydroxyl group and R is chosen from a C₁-C₂            alkyl radical, and an amino radical substituted with two            identical or different C₁-C₄ alkyl groups optionally bearing            at least one hydroxyl group, said alkyl radicals optionally            forming, with the nitrogen atom to which they are attached,            a 5- or 6-membered heterocycle optionally comprising at            least one other nitrogen or non-nitrogen hetero atom.

In an embodiment, R₁, R′₁, R′₂ and R′₃, which may be identical ordifferent, are chosen from:

-   -   a hydrogen atom;    -   an optionally substituted C₁-C₆ alkyl radical;    -   an aryl and arylalkyl radical, such as phenyl or benzyl, the        aryl part is optionally substituted;    -   R₁ may form, with all or part of the group LK and with the        nitrogen atom to which each is attached, a saturated and        unsaturated, aromatic and non-aromatic, optionally substituted        5- to 7-membered heterocycle;    -   R′₁, R′₂ or R′₃ together or separately, may form, with all or        part of the group LK and with the nitrogen or oxygen atom to        which each is attached, a saturated and unsaturated, aromatic        and non-aromatic, optionally substituted 5- to 7-membered        heterocycle.

In another embodiment, R₁, R′₁, R′₂ and R′₃, which may be identical ordifferent, are chosen from:

-   -   a hydrogen atom;    -   an optionally substituted C₁-C₃ alkyl radical, such as methyl,        ethyl, 2-hydroxyethyl or 2-methoxyethyl;    -   a phenyl radical; optionally substituted with at least one        radical chosen from hydroxyl, C₁-C₂ alkoxy and amino radicals        and amino radicals substituted with at least one C₁-C₄ groups        optionally bearing at least one hydroxyl group;    -   R₁ or R′₂ and R′₃ may form, with the nitrogen, or oxygen atom        for R′₃, to which each is attached and all or part of the group        LK, a 5- to 7-membered heterocycle chosen from pyrrolidines,        piperidines, piperazines and homopiperazines optionally        substituted with at least one radical chosen from methyl,        hydroxyl, amino and (di)methylamino radicals.

In another embodiment, R₁, R′₁, R′₂ and R′₃, which may be identical ordifferent, are chosen from:

-   -   a hydrogen atom;    -   methyl, ethyl and 2-hydroxyethyl radicals;    -   a phenyl radical, optionally substituted with a radical chosen        from hydroxyl, methoxy, amino, (di)methylamino and        (di)(2-hydroxyethyl)amino radicals;    -   R₁ or R′₂ and R′₃ may form, with the nitrogen, or oxygen atom        for R′₃, to which each is attached and all or part of the group        LK, a 5- to 7-membered heterocycle chosen from pyrrolidine,        3-hydroxypyrrolidine, 3-dimethylaminopyrrolidine, piperidine,        2-(2-hydroxyethylpiperidine), 4-(aminomethyl)piperidine,        4-(2-hydroxyethyl)piperidine, 4-(dimethylamino)piperidine,        piperazine, 1-methylpiperazine, 1-(2-hydroxyethyl)piperazine,        1-(2-aminoethyl)piperazine, 1-hydroxyethylethoxypiperazine,        homopiperazine and 1-methyl-1,4-perhydrodiazepine.

In one embodiment, R₄, R₅, R₆, R′₆, R₇, R₈, R₁₀ and R₁₁, which may beidentical or different, for example, are chosen from:

-   -   a hydrogen atom for R₄, R₅, R₇, R₈, R₁₀ and R₁₁;    -   an, optionally substituted C₁-C₁₆, for example, C₁-C₈, alkyl        radical;    -   a halogen atom such as chlorine, fluorine or bromine;    -   a hydroxyl group;    -   a C₁-C₂ alkoxy radical; a C₂-C₄ (poly)hydroxyalkoxy radical;    -   an amino radical; an amino radical substituted with one or two        C₁-C₄ alkyl radicals, which may be identical or different,        optionally bearing at least one group chosen from a hydroxyl and        C₁-C₄ dialkylamino groups;    -   an alkylcarbonylamino radical (RCO—NR′—) wherein R is chosen        from a C₁-C₄ alkyl radical and R′ is chosen from a hydrogen and        a C₁-C₄ alkyl radical; a carbamoyl radical ((R)₂N—CO—) wherein        R, which may be identical or different, are each chosen from a        hydrogen atom and a C₁-C₄ alkyl radical optionally bearing at        least one hydroxyl group; an alkylsulfonylamino radical        (R′SO₂—NR—) wherein R is chosen from a hydrogen atom and a C₁-C₄        alkyl radical optionally bearing at least one hydroxyl group, R′        is chosen from a C₁-C₄ alkyl radical; an aminosulfonyl radical        ((R)₂N—SO₂—) wherein R, which may be identical or different, are        each chosen from a hydrogen atom and a C₁-C₄ alkyl radical        optionally bearing at least one hydroxyl group; and    -   a bond from W′₂ to W′₁ or to the group LK, or from W′₅ to W′₆ or        to the group LK.

In another embodiment, R₄, R₅, R₆, R′₆, R₇, R₈, R₁₀ and R₁₁, whichidentical or different, for example, are chosen from:

-   -   a hydrogen atom for R₄, R₅, R₆, R′₆, R₇, R₈, R₁₀ and R₁₁;    -   a C₁-C₄ alkyl radical optionally substituted with at least one        radical chosen from hydroxyl and acylamino radicals, or amino        radicals substituted with two identical or different C₁-C₂ alkyl        radicals, optionally bearing at least one hydroxyl group, or a        C₁-C₂ alkoxy radical;    -   an amino radical; an amino radical substituted with one or two        identical or different C₁-C₂ alkyl radicals, optionally bearing        at least one hydroxyl group; an acylamino radical; a carbamoyl        radical; a sulfonylamino radical;    -   a hydroxyl radical; a C₁-C₂ alkoxy radical; and    -   a bond from W′₂ to W′₁ or to the group LK, or from W′₅ to W′₆ or        to the group LK.

In another embodiment, R₄, R₅, R₆, R′₆, R₇, R₈, R₁₀ and R₁₁, which maybe identical or different, for example, are chosen from:

-   -   a hydrogen atom for R₄, R₅, R₆, R′₆, R₇, R₈, R₁₀ and R₁₁;    -   a methyl, ethyl, propyl, 2-hydroxyethyl, methoxy, ethoxy,        2-hydroxyethyloxy, 3-hydroxypropyloxy or 2-methoxyethyl radical;    -   a sulfonylamino radical; an amino, methylamino, dimethylamino,        2-hydroxyethylamino, 3-hydroxypropylamino or acylamino radical;        a hydroxyl radical;    -   chlorine atoms; and    -   bonds from W′₂ to W′₁ or to the group LK, or from W′₅ to W′₆ or        to the group LK.

R₉ may be, for example, chosen from a hydrogen atom or a C₁-C₁₅ alkylradical; a C₂-C₆ monohydroxyalkyl radical; a C₂-C₆-polyhydroxyalkylradical; a (C₁-C₆)alkoxy(C₂-C₆)alkyl radical; an optionally substitutedaryl radical, such as phenyl; an optionally substituted arylalkylradical, such as benzyl; a C₂-C₆ amidoalkyl radical; and a C₂-C₆aminoalkyl radical, the amine of which is substituted with two identicalor different, optionally substituted C₁-C₄ alkyl radicals; wherein R₉ issuch that the atom directly linked to the nitrogen atom is a carbonatom.

For example, R₉ may be chosen from a hydrogen atom, a C₁-C₆ alkylradical or a C₂-C₆ monohydroxyalkyl radical; a C₂-C₆ polyhydroxyalkylradical; a (C₁-C₆)alkoxy(C₂-C₆)alkyl radical; a phenyl radicaloptionally substituted with at least one chlorine atom, a hydroxylgroup, a group RCO—NH— wherein R is chosen from a C₁-C₄ alkyl radical oran amino radical substituted with two identical or different C₁-C₄ alkylradicals; a benzyl radical; a C₁-C₆ aminoalkyl radical; and a C₁-C₆aminoalkyl radical wherein the amine is substituted with two identicalor different C₁-C₄ alkyl radicals; wherein R₉ is such that the atomdirectly linked to the nitrogen atom is a carbon atom.

According to one embodiment, W₂, W₅, W′₂ and W′₅, which may be identicalor different, are each chosen from group of formula (a) or (c).

According to this embodiment X₁ for example, is chosen from a group CR₇.

For example, according to this embodiment, X₂ is chosen from a radicalCR₈.

For example, according to this embodiment, R₄, R₅, R₆, R′₆, R₇ and R₈,which may be identical or different, have the same meanings as above.

W₃ and W₄, which may be identical or different, for example, are eachchosen from heterocycle of formulae (1) to (3) below:

wherein R′₄, R′₅, R′₇, p, p′ and c are defined as above.

In one embodiment of the disclosure, W₃ and W₄ are not simultaneouslychosen from imidazolium group.

For example, R′₅ and R′₇ have the same definitions as R₉, with theexception of hydrogen.

In one embodiment of the disclosure, the cationic aromatic heterocyclicgroup is chosen from 2-imidazolium, 2-benzimidazolium, 2-pyridinium,3-pyridinium, 4-pyridinium, 2-quinolinium, 4-quinolinium, 3-pyrazolium,4-pyrazolium, 3-indazolium, 4-indazolium, 5-indazolium, 6-indazolium and7-indazolium.

According to another embodiment of the disclosure, W₃ and W₄, which maybe identical or different, are each chosen from cationic aromaticheterocycles chosen from 2-imidazolium, 2-pyridinium, 3-pyridinium,4-pyridinium, 2-quinolinium, 4-quinolinium, 3-pyrazolium, 4-pyrazolium,3-indazolium, 4-indazolium and 7-indazolium.

In one embodiment of the disclosure, LK may be chose from:

wherein

-   -   D and D′, which may be identical or different, are each chosen        from linear and branched, saturated and unsaturated C₁-C₁₄        hydrocarbon-based bonds, optionally interrupted with at least        one hetero atoms or with at least one groups bearing at least        one hetero atom, for example, chosen from oxygen and nitrogen;    -   the bond d links the arms D and D′ to the groups W₁, W₆, W′₂ and        W′₅;    -   q is greater than or equal to 1, for example, equal to 1 or 2;    -   the group R is chosen from    -   R₁₂, R₁₃, R′₁₂ and R′₁₃, which may be identical or different,        are each chosen from a C₁-C₁₅ alkyl radical; a C₁-C₆        monohydroxyalkyl radical; a C₂-C₆ polyhydroxy-alkyl radical; a        (C₁-C₆)alkoxy(C₁-C₆)alkyl radical; an aryl radical such as        phenyl; an arylalkyl radical such as benzyl; a C₁-C₆ amidoalkyl        radical; a C₁-C₆ aminoalkyl radical; a C₁-C₆ aminoalkyl radical        wherein the amine is substituted with at least one identical or        different C₁-C₄ alkyl, (C₁-C₆)alkylcarbonyl, acylamino or        (C₁-C₆)alkylsulfonyl radicals;    -   R₁₂ and R₁₃ may form, together with the nitrogen atom to which        they are attached, a 5-, 6- or 7-membered saturated cationic        ring that may comprise at least one hetero atoms, the cationic        ring optionally is substituted with a halogen atom, a hydroxyl        radical, a C₁-C₆ alkyl radical, a C₁-C₆ monohydroxyalkyl        radical, a C₂-C₆ polyhydroxyalkyl radical, a C₁-C₆ alkoxy        radical, an amido radical, a (C₁-C₆)alkylcarbonyl radical, a        thio radical, a C₁-C₆ thioalkyl radical, a (C₁-C₆)alkylthio        radical, an amino radical and an amino radical substituted with        at least one identical or different C₁-C₆ alkyl,        (C₁-C₆)alkylcarbonyl, acylamino or (C₁-C₆)alkylsulfonyl        radicals; for example, the cationic ring is unsubstituted;    -   R₁₂ or R₁₃ may form, with D or D′, a 5-, 6- or 7-membered        saturated cationic ring that may comprise at least one hetero        atoms, the cationic ring optionally is substituted with a        halogen atom, a hydroxyl radical, a C₁-C₆ alkyl radical, a C₁-C₆        monohydroxyalkyl radical, a C₂-C₆ polyhydroxyalkyl radical, a        C₁-C₆ alkoxy radical, an amido radical, a (C₁-C₆)alkylcarbonyl        radical, a thio radical, a C₁-C₆ thioalkyl radical, a        (C₁-C₆)alkylthio radical, an amino radical and an amino radical        substituted with at least one identical or different C₁-C₆        alkyl, (C₁-C₆)alkyl-carbonyl, acylamino or (C₁-C₆)alkylsulfonyl        radicals; for example, the cationic ring is unsubstituted;    -   R₁₂ and R₁₃ may form with W₁ or W₆ a 5-, 6- or 7-membered,        saturated and unsaturated, aromatic and non-aromatic, optionally        substituted cationic heterocycle;    -   the ring members E, G, J and L, which may be identical or        different, are each chosen from carbon, oxygen, sulfur or        nitrogen atom to form a ring chosen from pyrazolium,        imidazolium, triazolium, oxazolium, isoxazolium, thiazolium and        isothiazolium rings,    -   R₁₄ has the same meaning as R₁₂;    -   R₁₅ is chosen from a C₁-C₆ alkyl radical; a C₁-C₆        monohydroxyalkyl radical, a C₂-C₆ polyhydroxyalkyl radical, a        (C₁-C₆)alkoxy(C₁-C₆)alkyl radical, a C₂-C₆ carbamylalkyl        radical, a (C₁-C₆)alkylcarboxy(C₁-C₆)alkyl radical and a benzyl        radical; wherein R₁₅ is attached to a nitrogen atom,    -   R₁₆, which may be identical or different, are each chosen from        hydrogen or halogen atom, a C₁-C₆ alkyl radical, a C₁-C₆        monohydroxyalkyl radical, a C₂-C₆ polyhydroxyalkyl radical, a        C₁-C₆ alkoxy radical, an amido radical, a carboxyl radical, a        C₁-C₆ alkylcarbonyl radical, a C₁-C₆ thioalkyl radical, a        (C₁-C₆)alkylthio radical, an amino radical disubstituted with a        (C₁-C₆)alkyl, (C₁-C₆)alkylcarbonyl or (C₁-C₆)alkylsulfonyl        radical, a benzyl radical, and a phenyl radical optionally        substituted with at least one radical chosen from methyl,        hydroxyl, amino and methoxy radicals, wherein, R₁₆ is attached        to a carbon atom,    -   An is chosen from an organic or mineral anion;    -   z is an number ranging from 1 to 3;    -   y is equal to 0 or 1;    -   v is equal to 1 or 2;    -   x is equal to 0 or 1;        -   wherein x=0, then one of the linker arms D or D′ is attached            to the quaternized nitrogen atom,        -   wherein x=1, at least one of the linker arms D and/or D′ is            attached to a carbon atom.

According to one embodiment of formula (d), R₁₂ and R₁₃, which may beidentical or different, are for example, chosen from a C₁-C₆ alkylradical, a C₁-C₄ monohydroxyalkyl radical, a C₂-C₄ polyhydroxyalkylradical, a (C₁-C₆)alkoxy(C₂-C₄)alkyl radical, a C₂-C₆ amidoalkyl radicalor a C₂-C₆ dimethylaminoalkyl radical.

By further example, R₁₂ and R₁₃, which may be identical or different,are each chosen from methyl, ethyl or 2-hydroxyethyl radical.

According to this embodiment, D and D′, which may be identical ordifferent, are for example, a C₁-C₆ alkyl chain that may be substituted,and is, for example, unsubstituted.

According to one embodiment of formula (e), the ring members E, G, J andL form a ring chosen from imidazolium, pyrazolium, oxazolium andthiazolium rings.

According to this embodiment, x and b are equal to 0.

In this embodiment, D and D′ are each chosen from C₁-C₄ alkyl chain thatmay be substituted, and is, for example, unsubstituted.

Moreover, R₁₄, for example, is chosen from a methyl, ethyl and2-hydroxyethyl radical.

According to one embodiment of formula (f), R′₁₂ and R′₁₃ have the samemeanings as R₁₂ and R₁₃.

According to this embodiment, D and D′, which may be identical ordifferent, are, for example, a C₁-C₆ alkyl chain that may besubstituted, and is, for example, unsubstituted.

For example, in one embodiment, the coefficient v is equal to 1.

An may be chosen from an organic or mineral anion or mixture of anions,so as to respect the electrical neutrality of the compound, for examplechosen from halides such as chlorides, bromides, fluorides or iodides;hydroxides; sulfates; hydrogen sulfates; (C₁-C₆)alkyl sulfates, forinstance methyl sulfate or ethyl sulfate; phosphates; carbonates;hydrogen carbonates; perchlorates; acetates; tartrates; citrates;oxalates; (C₁-C₆)-alkylsulfonates such as methylsulfonate; andarylsulfonates, which are unsubstituted or substituted with a C₁-C₄alkyl radical, for instance a 4-tolylsulfonate.

The addition salts with an acid of the compounds of formula (I) may bechosen from, for example, halides, for instance chlorides or bromides,sulfates, alkyl sulfates for which the linear and branched alkyl part isof C₁-C₆, for instance methosulfate or ethosulfate ions, hydrogencarbonates, perchlorates, carboxylic acid salts, for instance acetates;citrates; tartrates, alone or in combination.

In one embodiment of the disclosure, the compounds of formula (I) arechosen from:

wherein formulae:

-   -   R₁, R₃, R₄, R₁₂, R₁₃, R′₄, R′₅, R′₇, R′₁₂, R′₁₃, p and p′ are        defined as above;    -   r and r′, which may be identical or different, are numbers        ranging from 1 to 10, for example, from 1 to 6;    -   wherein, the electrical neutrality of the molecule is respected        by the presence of at least one cosmetically acceptable anion An        as defined above.

For example, R₃, R₄ and R′₄ are each chosen from a hydrogen atom.

These compounds may be obtained from preparation processes described,for example, in documents U.S. Pat. No. 5,708,151, J. Chem. Res., Synop.(1998), (10), 648-649, U.S. Pat. No. 3,151,106, U.S. Pat. No. 5,852,179,Heterocycles, 1987, 26 (2) 313-317, Synth. Commun. 1999, 29(13),2271-2276, Tetrahedron,1983, 39(7),1091-1101.

Another embodiment is a composition comprising, in a medium that issuitable for dyeing keratin fibers, at least one compound of formula(I), or an addition salt thereof with an acid, as direct dye, whereinDYE1, LK and DYE2 are defined as above.

The concentration of the at least one compound of formula (I) may rangefrom 0.001% to 20% by weight, for example, from 0.01% to 10% by weightand further, for example, from 0.05% to 5% by weight, relative to thetotal weight of the dye composition.

In one embodiment, the composition according to the disclosure may alsocomprise at least one oxidation base. This at least one oxidation basemay be chosen from the oxidation bases conventionally used in oxidationdyeing, for example ortho-phenylenediamines, para-phenylenediamines,double bases such as bis(phenyl)alkylenediamines; para-aminophenols,ortho-aminophenols and heterocyclic bases and the addition salts thereofwith an acid.

Among the para-phenylenediamines that may be mentioned are, for example,para-phenylenediamine, para-tolylenediamine,2-chloro-para-phenylenediamine, 2,3-dimethyl-para-phenylenediamine,2,6-dimethyl-para-phenylenediamine, 2,6-diethyl-para-phenylenediamine,2,5-dimethyl-para-phenylenediamine, N,N-dimethyl-para-phenylenediamine,N,N-diethyl-para-phenylenediamine, N,N-dipropyl-para-phenylenediamine,4-amino-N,N-diethyl-3-methylaniline,N,N-bis(β-hydroxyethyl)-para-phenylenediamine,4-N,N-bis(β-hydroxyethyl)amino-2-methylaniline,4-N,N-bis(β-hydroxyethyl)amino-2-chloroaniline,2-β-hydroxyethyl-para-phenylenediamine, 2-fluoro-para-phenylenediamine,2-isopropyl-para-phenylenediamine,N-(β-hydroxypropyl)-para-phenylenediamine,2-hydroxymethyl-para-phenylenediamine,N,N-dimethyl-3-methyl-para-phenylenediamine,N-ethyl-N-(β-hydroxyethyl)-para-phenylenediamine,N-(β,γ-dihydroxypropyl)-para-phenylenediamine,N-(4′-aminophenyl)-para-phenylenediamine,N-phenyl-para-phenylenediamine,2-β-hydroxyethyloxy-para-phenylenediamine,2-β-acetylaminoethyloxy-para-phenylenediamine,N-(β-methoxyethyl)-para-phenylenediamine, 4-aminophenylpyrrolidine,2-thienyl-para-phenylenediamine, 2-β-hydroxyethylamino-5-aminotoluene,and the addition salts thereof with an acid.

For example, the para-phenylenediamines may be chosen frompara-phenylenediamine, para-tolylenediamine,2-isopropyl-para-phenylenediamine,2-β-hydroxyethyl-para-phenylenediamine,2-p-hydroxyethyloxy-para-phenylenediamine,2,6-dimethyl-para-phenylenediamine, 2,6-diethyl-para-phenylenediamine,2,3-dimethyl-para-phenylenediamine,N,N-bis(,-hydroxyethyl)-para-phenylenediamine,2-chloro-para-phenylenediamine and2-β-acetylaminoethyloxy-para-phenylenediamine, and the addition saltsthereof with an acid.

Among the bis(phenyl)alkylenediamines that may be mentioned, forexample, areN,N′-bis(β-hydroxyethyl)-N,N′-bis(4′-aminophenyl)-1,3-diaminopropanol,N,N′-bis-(β-hydroxyethyl)-N,N′-bis(4′-aminophenyl)ethylenediamine,N,N′-bis(4-aminophenyl)tetra-methylenediamine,N,N′-bis(β-hydroxyethyl)-N,N′-bis(4-aminophenyl)tetramethylenediamine,N,N′-bis(4-methylaminophenyl)tetramethylenediamine,N,N′-bis(ethyl)-N,N′-bis(4′-amino-3′-methylphenyl)ethylenediamine and1,8-bis(2,5-diaminophenoxy)-3,6-dioxaoctane, and the addition saltsthereof with an acid.

Among the para-aminophenols that may be mentioned, for example, arepara-aminophenol, 4-amino-3-methylphenol, 4-amino-3-fluorophenol,4-amino-3-hydroxymethylphenyol, 4-amino-2-methylphenol,4-amino-2-hydroxymethylphenol, 4-amino-2-methoxymethylphenol,4-amino-2-aminomethylphenol,4-amino-2-(β-hydroxyethylamino-methyl)phenol and 4-amino-2-fluorophenol,and the addition salts thereof with an acid.

Among the ortho-aminophenols that may be mentioned, for example, are2-aminophenol, 2-amino-5-methylphenol, 2-amino-6-methylphenol and5-acetamido-2-aminophenol, and the addition salts thereof with an acid.

Among the heterocyclic bases that may be mentioned, for example, arepyridine derivatives, pyrimidine derivatives and pyrazole derivatives.

Among the pyridine derivatives that may be mentioned are the compoundsdescribed, for example, in UK Patent Nos. GB 1 026 978 and GB 1 153 196,such as 2,5-diaminopyridine, 2-(4-methoxyphenyl)amino-3-aminopyridine,2,3-diamino-6-methoxy-pyridine,2-(β-methoxyethyl)amino-3-amino-6-methoxypyridine and3,4-diaminopyridine, and the addition salts thereof with an acid.

Among the pyrimidine derivatives that may be mentioned are the compoundsdescribed, for example, in German Patent No. DE 2 359 399; JapanesePatent Nos. JP 88-169 571; JP 05-163 124; and European Patent No. EP 0770 375 or PCT Patent Application No. WO 96/15765, such as2,4,5,6-tetraaminopyrimidine, 4-hydroxy-2,5,6-triaminopyrimidine,2-hydroxy-4,5,6-triaminopyrimidine, 2,4-dihydroxy-5,6-diaminopyrimidineand 2,5,6-triaminopyrimidine, and pyrazolopyrimidine derivatives such asthose mentioned in French Patent Application No. FR-A-2 750 048 andamong which non-limiting mention may be made ofpyrazolo[1,5-a]pyrimidine-3,7-diamine;2,5-dimethylpyrazolo[1,5-a]pyrimidine-3,7-diamine;pyrazolo[1,5-a]pyrimidine-3,5-diamine;2,7-dimethylpyrazolo[1,5-a]pyrimidine-3,5-diamine;3-aminopyrazolo[1,5-a]pyrimidin-7-ol;3-aminopyrazolo[1,5-a]pyrimidin-5-ol;2-(3-aminopyrazolo[1,5-a]pyrimidin-7-ylamino)ethanol,2-(7-aminopyrazolo[1,5-a]pyrimidin-3-ylamino)ethanol,2-[(3-aminopyrazolo[1,5-a]pyrimidin-7-yl)(2-hydroxyethyl)amino]ethanol,2-[(7-aminopyrazolo[1,5-a]pyrimidin-3-yl)(2-hydroxy-ethyl)amino]ethanol,5,6-dimethylpyrazolo[1,5-a]pyrimidine-3,7-diamine,2,6-dimethylpyrazolo[1,5-a]pyrimidine-3,7-diamine,2,5,N7,N7-tetramethylpyrazolo[1,5-a]pyrimidine-3,7-diamine and3-amino-5-methyl-7-imidazolylpropylaminopyrazolo[1,5-a]-pyrimidine, andthe addition salts thereof with an acid and the tautomeric formsthereof, when a tautomeric equilibrium exists.

Among the pyrazole derivatives that may be mentioned are the compoundsdescribed in German Patent Nos. DE 3 843 892 and DE 4 133 957 and PCTPatent Application Nos. WO 94/08969, WO 94/08970, French PatentApplication No. FR-A-2 733 749 and German Patent Application No. DE 19543 988, such as 4,5-diamino-1-methylpyrazole,4,5-diamino-1-(β-hydroxyethyl)pyrazole, 3,4-diaminopyrazole,4,5-diamino-1-(4′-chlorobenzyl)pyrazole,4,5-diamino-1,3-dimethylpyrazole, 4,5-diamino-3-methyl-1-phenylpyrazole,4,5-diamino-1-methyl-3-phenylpyrazole, 4-amino-1,3-dimethyl-5-hydrazinopyrazole, 1-benzyl-4,5-diamino-3-methylpyrazole,4,5-diamino-3-tert-butyl- 1-methylpyrazole,4,5-diamino-1-tert-butyl-3-methylpyrazole, 4,5-diamino-1-(β-hydroxyethyl)-3-methylpyrazole,4,5-diamino-1-ethyl-3-methylpyrazole, 4,5-diamino-1-ethyl-3-(4′-methoxyphenyl)pyrazole,4,5-diamino-1-ethyl-3-hydroxymethylpyrazole,4,5-diamino-3-hydroxymethyl-1-methylpyrazole,4,5-diamino-3-hydroxymethyl-1-isopropylpyrazole,4,5-diamino-3-methyl-1-isopropylpyrazole,4-amino-5-(2′-aminoethyl)amino-1,3-dimethylpyrazole,3,4,5-triaminopyrazole, 1-methyl-3,4,5-triaminopyrazole,3,5-diamino-1-methyl-4-methylaminopyrazole and3,5-diamino-4-(β-hydroxyethyl)amino-1-methylpyrazole, and the additionsalts thereof with an acid.

The composition according to the disclosure may also comprise at leastone couplers conventionally used for dyeing keratin fibers. Among thesecouplers, non-limiting mention may be made, for example, ofmeta-phenylenediamines, meta-aminophenols, meta-diphenols,naphthalene-based couplers and heterocyclic couplers, the addition saltsthereof with an acid, and also mixtures thereof.

Couplers that may be mentioned are chosen from 2-methyl-5-aminophenol,5-N-(β-hydroxyethyl)amino-2-methylphenol,6-chloro-2-methyl-5-aminophenol, 3-aminophenol, 1,3-dihydroxybenzene,1,3-dihydroxy-2-methylbenzene, 4-chloro-1,3-dihydroxybenzene,2,4-diamino-1-(β-hydroxyethyloxy)benzene,2-amino-4-(β-hydroxy-ethylamino)-1-methoxybenzene, 1,3-diaminobenzene,1,3-bis(2,4-diaminophenoxy)propane, 3-ureidoaniline,3-ureido-1-dimethylaminobenzene, sesamol,1-β-hydroxyethylamino-3,4-methylenedioxybenzene, α-naphthol,2-methyl-1-naphthol, 6-hydroxyindole, 4-hydroxyindole,4-hydroxy-N-methylindole, 2-amino-3-hydroxypyridine,6-hydroxybenzomorpholine, 3,5-diamino-2,6-dimethoxypyridine,1-N-(β-hydroxyethyl)-amino-3,4-methylenedioxybenzene and2,6-bis(β-hydroxyethylamino)toluene and the addition salts thereof withan acid.

In the composition of the present disclosure, the at least one couplermay be present in an amount ranging from 0.001% to 10% by weight, forexample, from 0.005% to 6% by weight, relative to the total weight ofthe dye composition. The at least one oxidation base may be present inan amount, for example, ranging from 0.001% to 10% by weight, andfurther, for example, from 0.005% to 6% by weight, relative to the totalweight of the dye composition.

For example, the addition salts with an acid that may be used in thecontext of the dye compositions of the disclosure for the oxidationbases and couplers are chosen, for example, from the hydrochlorides,hydrobromides, sulfates, citrates, succinates, tartrates, lactates,tosylates, benzenesulfonates, phosphates and acetates.

The composition according to the disclosure may optionally comprise atleast one additional direct dye other than the compounds of formula (I).This dye may be chosen from cationic and nonionic species.

Non-limiting-examples of the at least one additional direct dye thatmay-be mentioned are chosen from nitrobenzene dyes, azo, azomethine,methine, tetraazapentamethine, anthraquinone, naphthoquinone,benzoquinone, phenothiazine, indigoid, xanthene, phenanthridine,phthalocyanin and triarylmethane-based dyes and natural dyes, alone oras mixtures.

The at least one additional direct dye may be chosen, for example, fromthe following red or orange nitrobenzene dyes:

-   1-hydroxy-3-nitro-4-N-(γ-hydroxypropyl)aminobenzene,-   N-(β-hydroxyethyl)amino-3-nitro-4-aminobenzene,-   1-amino-3-methyl-4-N-(β-hydroxyethyl)amino-6-nitrobenzene,-   1-hydroxy-3-nitro-4-N-(β-hydroxyethyl)aminobenzene,-   1,4-diamino-2-nitrobenzene,-   1-amino-2-nitro-4-methylaminobenzene,-   N-(β-hydroxyethyl)-2-nitro-para-phenylenediamine,-   1-amino-2-nitro-4-(β-hydroxyethyl)amino-5-chlorobenzene,-   2-nitro-4-aminodiphenylamine,-   1-amino-3-nitro-6-hydroxybenzene,-   1-(β-aminoethyl)amino-2-nitro-4-(β-hydroxyethyloxy)benzene,-   1-(β,γ-dihydroxypropyl)oxy-3-nitro-4-(β-hydroxyethyl)aminobenzene,-   1-hydroxy-3-nitro-4-aminobenzene,-   1-hydroxy-2-amino-4,6-dinitrobenzene,-   1-methoxy-3-nitro-4-(β-hydroxyethyl)aminobenzene,-   2-nitro-4′-hydroxydiphenylamine, and-   1-amino-2-nitro-4-hydroxy-5-methylbenzene.

The at least one additional direct dye may also be chosen from yellowand green-yellow nitrobenzene direct dyes; non-limiting mention may bemade, for example, -of the compounds chosen from:

-   1-β-hydroxyethyloxy-3-methylamino-4-nitrobenzene,-   1-methylamino-2-nitro-5-(β,γ-dihydroxypropyl)oxybenzene,-   1-(β-hydroxyethyl)amino-2-methoxy-4-nitrobenzene,-   1-(β-aminoethyl)amino-2-nitro-5-methoxybenzene,-   1,3-di(β-hydroxyethyl)amino-4-nitro-6-chlorobenzene,-   1-amino-2-nitro-6-methylbenzene,-   1-(β-hydroxyethyl)amino-2-hydroxy-4-nitrobenzene,-   N-(β-hydroxyethyl)-2-nitro-4-trifluoromethylaniline,-   4-(β-hydroxyethyl)amino-3-nitrobenzenesulfonic acid,-   4-ethylamino-3-nitrobenzoic acid,-   4-(β-hydroxyethyl)amino-3-nitrochlorobenzene,-   4-(β-hydroxyethyl)amino-3-nitromethylbenzene,-   4-(β,γ-dihydroxypropyl)amino-3-nitrotrifluoromethylbenzene,-   1-(β-ureidoethyl)amino-4-nitrobenzene,-   1,3-diamino-4-nitrobenzene,-   1-hydroxy-2-amino-5-nitrobenzene,-   1-amino-2-[tris(hydroxymethyl)methyl]amino-5-nitrobenzene,-   1-(β-hydroxyethyl)amino-2-nitrobenzene, and-   4-(β-hydroxyethyl)amino-3-nitrobenzamide.

Mention may also be made of blue or violet nitrobenzene direct dyes, forinstance:

-   1-(β-hydroxyethyl)amino-4-N,N-bis(β-hydroxyethyl)amino-2-nitrobenzene,-   1-(γ-hydroxypropyl)amino-4,N,N-bis(β-hydroxyethyl)amino-2-nitrobenzene,-   1-(β-hydroxyethyl)amino-4-(N-methyl-N-β-hydroxyethyl)amino-2-nitrobenzene,-   1-(β-hydroxyethyl)amino-4-(N-ethyl-N-β-hydroxyethyl)amino-2-nitrobenzene,-   1-(β,γ-dihydroxypropyl)amino-4-(N-ethyl-N-β-hydroxyethyl)amino-2-nitrobenzene,-   2-nitro-para-phenylenediamines of the following formula:    wherein:    -   R_(b) is chosen from a C₁-C₄ alkyl radical and a β-hydroxyethyl,        β-hydroxypropyl and γ-hydroxypropyl radical;    -   R_(a) and R_(c), which may be identical or different, are each        chosen from β-hydroxyethyl, β-hydroxypropyl, γ-hydroxypropyl and        β,γ-dihydroxypropyl radicals, wherein at least one of R_(b),        R_(c) or R_(a) is chosen from a γ-hydroxypropyl radical wherein        R_(b) and R_(c) are not simultaneously a β-hydroxyethyl radical        when R_(b) is a γ-hydroxypropyl radical, such as those described        in French Patent No. FR 2 692 572.

Among the azo direct dyes that may be used according to the disclosure,non-limiting mention may be made of the cationic azo dyes described inPCT Patent Application Nos. WO 95/15144, WO 95/01772 and European PatentApplication No. EP 714 954.

Among azo direct dyes, non-limiting mention may be made of the followingdyes:

1,3-dimethyl-2-[[4-(dimethylamino)phenyl]azo]-1H-imidazolium chloride,

1,3-dimethyl-2-[(4-aminophenyl)azo]-1H-imidazolium chloride,

1-methyl-4-[(methylphenylhydrazono)methyl]pyridinium methyl sulfate.

Among the azo direct dyes that may also be mentioned are the followingdyes described in the Color Index International 3rd edition:

Disperse Red 17

Acid Yellow 9

Acid Black 1

Basic Red 22

Basic Red 76

Basic Yellow 57

Basic Brown 16

Acid Yellow 36

Acid Orange 7

Acid Red 33

Acid Red 35

Basic Brown 17

Acid Yellow 23

Acid Orange 24

Disperse Black 9.

Mention may also be made of1-(4′-aminodiphenylazo)-2-methyl-4-[bis(β-hydroxyethyl)amino]benzene and4-hydroxy-3-(2-methoxyphenylazo)-1-naphthalenesulfonic acid.

Among the quinone direct dyes that may be mentioned are the followingdyes:

Disperse Red 15

Solvent Violet 13

Acid Violet 43

Disperse Violet 1

Disperse Violet 4

Disperse Blue 1

Disperse Violet 8

Disperse Blue 3

Disperse Red 11

Acid Blue 62

Disperse Blue 7

Basic Blue 22

Disperse Violet 15

Basic Blue 99

and also the following compounds:

1-N-methylmorpholiniumpropylamino-4-hydroxyanthraquinone

1-aminopropylamino-4-methylaminoanthraquinone

1-aminopropylaminoanthraquinone

5-β-hydroxyethyl-1,4-diaminoanthraquinone

2-aminoethylaminoanthraquinone

1,4-bis(β,γ-dihydroxypropylamino)anthraquinone.

Among the azine dyes that may be mentioned are the following compounds:

Basic Blue 17

Basic Red 2.

Among the triarylmethane dyes that may be used according to thedisclosure, non-limiting mention may be made of the following compounds:

Basic Green 1

Acid Blue 9

Basic Violet 3

Basic Violet 14

Basic Blue 7

Acid Violet 49

Basic Blue 26

Acid Blue 7.

Among the indoamine dyes that may be used according to the disclosure,non-limiting mention may be made of the following compounds:

2-β-hydroxyethylamino-5-[bis(β-4′-hydroxyethyl)amino]anilino-1,4-benzoquinone;

2-β-hydroxyethylamino-5-(2′-methoxy-4′-amino)anilino-1,4-benzoquinone;

3-N(2′-chloro-4′-hydroxy)phenylacetylamino-6-methoxy-1,4-benzoquinoneimine;

3-N(3′-chloro-4′-methylamino)phenylureido-6-methyl-1,4-benzoquinoneimine;

3-[4′-N-(ethylcarbamylmethyl)amino]phenylureido-6-methyl-1,4-benzoquinoneimine.

Among the dyes of tetraazapentamethine type that may be used accordingto the disclosure, non-limiting mention may be made of the followingcompounds, wherein An is defined as above:

Among the natural direct dyes that may be used according to thedisclosure, non-limiting mention may be made of lawsone, juglone,alizarin, purpurin, carminic acid, kermesic acid, purpurogallin,protocatechaldehyde, indigo, isatin, curcumin, spinulosin andapigenidin. Extracts or decoctions comprising these natural dyes mayalso be used, for example, henna-based poultices or extracts.

The at least one additional direct dye may be present in an amountranging from 0.001% to 20% by weight, relative to the weight of thecomposition , for example, from 0.01% to 10% by weight, relative to theweight of the composition.

The medium that is suitable for dyeing, also known as the dye support,may comprise water or of a mixture of water and of at least one organicsolvent to dissolve the compounds that are not sufficientlywater-soluble.

For example, the at least one organic solvent may be chosen from linearand branched, for example, saturated, monoalcohols or diols comprisingfrom 2 to 10 carbon atoms, such as ethyl alcohol, isopropyl alcohol,hexylene glycol (2-methyl-2,4-pentanediol), neopentyl glycol and3-methyl-1,5-pentanediol; aromatic alcohols such as benzyl alcohol andphenylethyl alcohol; glycols or glycol ethers, for instance ethyleneglycol monomethyl, monoethyl and monobutyl ether, propylene glycol andits ethers, for instance propylene glycol monomethyl ether, butyleneglycol and dipropylene glycol; and also diethylene glycol alkyl ethers,for example, of C₁-C₄, for instance diethylene glycol monoethyl ether ormonobutyl ether, alone or as a mixture.

The at least one organic solvent may be present in an amount rangingfrom 1% to 40% by weight, for example, from 5% to 30% by weight,relative to the total weight of the composition.

The dye composition disclosed herein may also comprise at least oneadjuvant conventionally used in compositions for dyeing the hair chosenfrom anionic, cationic, nonionic, amphoteric or zwitterionic surfactantsor mixtures thereof, anionic, cationic, nonionic, amphoteric orzwitterionic polymers or mixtures thereof, mineral or organicthickeners, for example, anionic, cationic, nonionic and amphotericassociative polymeric thickeners, antioxidants, penetrating agents,sequestering agents, fragrances, buffers, dispersants, conditioningagents, for instance silicones, which may or may not be volatile ormodified, film-forming agents, ceramides, preserving agents andopacifiers.

The at least one adjuvants may be present in an amount ranging from0.01% and 20% by weight, relative to the weight of the composition.

A person skilled in the art will take care to select these optionaladditional compounds such that the advantageous properties intrinsicallyassociated with the oxidation dye composition of the disclosure are not,or are not substantially, adversely affected by the envisagedaddition(s).

The pH of the dye composition of the disclosure ranges from 3 to 12, forexample, from 5 to 11. It may be adjusted to the desired value using oneor more acidifying or basifying agents usually used in the dyeing ofkeratin fibers, or by using standard buffer systems.

Among the acidifying agents that may be mentioned, for example, aremineral or organic acids such as hydrochloric acid, orthophosphoricacid, sulfuric acid, carboxylic acids such as acetic acid, tartaricacid, citric acid and lactic acid, and sulfonic acids.

Among the basifying agents that may be mentioned, for example, areaqueous ammonia, alkaline carbonates, alkanolamines such asmonoethanolamine, diethanolamine and triethanolamine and derivativesthereof, sodium hydroxide, potassium hydroxide and the compounds of thefollowing formula:

wherein W is a propylene residue optionally substituted with a hydroxylgroup or a C₁-C₄ alkyl radical; R_(a), R_(b), R_(c) and R_(d), which maybe identical or different, are each chosen from a hydrogen atom, a C₁-C₄alkyl radical or a C₁-C₄ hydroxyalkyl radical.

The dye composition according to the disclosure may be in various formschosen from liquids, creams or gels, and in any other form that issuitable for dyeing keratin fibers, for example, human hair.

The composition according to the disclosure may also comprise at leastone oxidizing agent. In this case, the composition is referred to as aready-to-use composition.

For the purposes of the present disclosure, the term “ready-to-usecomposition” means a composition intended to be applied immediately tothe keratin fibers, i.e. it may be stored in unmodified form before useor may result from the extemporaneous mixing of two or morecompositions.

The composition according to the disclosure may also be obtained bymixing the composition according to the disclosure with an oxidizingcomposition.

The at least one oxidizing agent may be any oxidizing agentconventionally used in the field. Thus, it may be chosen from hydrogenperoxide, urea peroxide, alkali metal bromates, persalts such asperborates and persulfates, and also enzymes, among which mention may bemade of peroxidases, 2-electron oxidoreductases such as uricases, and4-electron oxygenases, for instance laccases. For example, the oxidizingagent may be hydrogen peroxide.

The content of oxidizing agent ranges from 1% to 40% by weight relativeto the weight of the ready-to-use composition, for example, from 1% to20% by weight relative to the weight of the ready-to-use composition.

For example, the oxidizing composition used may be an aqueouscomposition and may be in the form of a solution or an emulsion.

For example, the composition free of oxidizing agent may be mixed with0.5 to 10 weight equivalents of the oxidizing composition.

The pH of the ready-to-use composition may, for example, range from 4 to12, for example, from 7 to 11.5.

The pH of the composition may be adjusted using an acidifying orbasifying agent chose, for example, from those mentioned previously inthe context of the description according to the disclosure.

Another embodiment of the disclosure is also a dyeing process thatcomprises the application of a dye composition according to thedisclosure to wet or dry keratin fibers.

The application to the fibers of the dye composition comprising thecompound(s) of formula (I) or the addition salts thereof with an acid,optionally at least one oxidation base optionally combined with at leastone coupler, and optionally at least one additional direct dye, may beperformed in the presence of an oxidizing agent.

This oxidizing agent may be added to the composition comprising the atleast one compound of formula (I) and the optional oxidation bases,couplers and optional additional direct dyes, either at the time of useor directly onto the keratin fiber.

The oxidizing composition may also comprise various adjuvantsconventionally used in compositions for dyeing the hair and as definedabove.

The pH of the oxidizing composition comprising the oxidizing agent issuch that, after mixing with the dye composition, the pH of theresulting composition applied to the keratin fibers may, for example,range from 4 to 12, for example, from 7 to 11.5. It may be adjusted tothe desired value by means of acidifying or basifying agents usuallyused in the dyeing of keratin fibers and as defined above.

The composition that is finally applied to the keratin fibers may be invarious forms chosen from liquids, creams, gels and in any other formthat is suitable for dyeing keratin fibers, for example, human hair.

According to one embodiment, the composition according to the disclosureis free of oxidation base and of coupler.

The composition applied may optionally comprise at least one oxidizingagent.

The composition is thus applied to the wet or dry keratin fibers and isthen: left for a leave-in time that is sufficient to obtain the desiredcoloration.

Whatever the embodiment adopted (with or without oxidizing agent), theleave-in time ranges from a few seconds to one hour, for example,ranging from 3 to 30 minutes.

The temperature at which the composition is left to act may range from15 to 220° C., for example, from 15 to 80° C. and further, for example,from 15 to 40° C.

After the leave-in time, the composition is removed by rinsing withwater, optionally followed by washing with a shampoo, and thenoptionally drying.

Another embodiment of the disclosure is a multi-compartment device ordyeing “kit” wherein at least one compartment comprises at least one dyecomposition of the disclosure and at least one compartment comprises atleast one oxidizing composition. This device may be equipped with ameans for applying the desired mixture to the hair, such as the devicesdescribed in French Patent No. FR-2 586 913.

Other than in the operating examples, and where otherwise indicated, allnumbers expressing quantities of ingredients, reaction conditions, andso forth used in the specification and claims are to be understood asmodified in all instances by the term “about.” Accordingly, unlessindicated to the contrary, the numerical parameters set forth in thisspecification and attached claims are approximations that may varydepending upon the desired properties sought to be obtained by thepresent disclosure. At the very least, and not as an attempt to limitthe application of the doctrine of equivalents to the scope of theclaims, each numerical parameter should be construed in light of thenumber of significant digits and ordinary rounding approaches.

Notwithstanding that the numerical ranges and parameters setting forththe broad scope of the disclosure are approximations, the numericalvalues set forth in the specific examples are reported as precisely aspossible. Any numerical value, however, inherently contains certainerrors necessarily resulting from the standard deviation found in theirrespective testing measurements.

The following examples are intended to illustrate the disclosure in anon-limiting manner.

EXAMPLE 1

1/Synthesis of Compound 6:

ProcedureStep 1

Compound 1 (1 g) was placed in 12 ml of water in a three-necked flaskwith stirring; 3-aminopropylimidazole (2.8 ml; 8 eq.) was then added tothe reaction medium. The mixture was heated to 75° C. (externaltemperature) with stirring.

After 15 minutes, the heating was stopped and the mixture was allowed tocool to room temperature.

After precipitation of the product from acetone, followed by filtration,compound 2 was recovered. A dark purple-red solid was obtained. The NMRand mass spectra were in accordance with compound 2.

Step 2

Compound 3 (20 g) and ethanol (200 ml) were placed in a three-neckedflask and 6-aminohexanol (43.9 g, 5 eq.) was introduced.

The mixture was heated to 70° C. (external temperature) with stirring.

After 10 hours, the heating was stopped and the mixture was allowed tocool to room temperature.

After evaporation of the solvent, compound 4 was recovered.

A red solid was obtained. The NMR and mass spectra were in accordancewith compound 4.

Step 3

Compound 4 (3 g),1,3-dimethyl-3,4,5,6-tetrahydro-2(1H)-pyrimidinone (80ml), methanesulfonyl chloride (4 ml, 6 eq.) and pyridine (4.12 ml, 6eq.) were placed in a three-necked flask.

The mixture was stirred at room temperature for4 days.

The product was precipitated from ethyl acetate and then filtered off.The precipitate was dissolved in water and then extracted withdichloromethane. The organic phase was dried over sodium sulfate,filtered and then concentrated.

Compound 5 was recovered in the form of a matte-red powder.

The NMR and mass spectra were in accordance with compound 5.

Step 4

Compounds 2 and 5,1,3-dimethyl-3,4,5,6-tetrahydro-2(1H)-pyrimidinone (4ml) and a catalytic amount of KI were placed in a three-necked flask.

The mixture was stirred at 95° C. for 14 hours.

The product was precipitated from ethyl acetate and then filtered. Theprecipitate was washed several times with dichloromethane. Compound 6was recovered in the form of a matte dark purple powder.

The NMR and mass spectra show that compound 5 had been synthesized.

Dyeing Example

The composition below was prepared: Ingredients Amount (50/50 C8/C10)Alkyl polyglucoside (2) as a buffered 60% 12 g aqueous solution Pureabsolute ethanol 20 g Pure benzyl alcohol 4 g Polyethylene glycol 400 (8EO) 6 g Demineralized water qs 100 g

5×10⁻³ mol, of compound 6 were dissolved in the composition describedabove.

The composition thus obtained was applied to locks of hair containing90% white hairs.

A fuchsia shade was obtained with compound 6.

EXAMPLE 2

Synthesis of Compound 8:

ProcedureStep 1

Compound 1 (1 g) was placed in 10 ml of water in a three-necked flaskwith stirring; N-methylpiperazine (3.3 ml; 10 eq.) was then added to thereaction medium. The mixture was left at room temperature with stirring.

After 1 hour, the reaction medium was precipitated from 50 ml ofacetone.

After filtering off the precipitate, compound 7 was recovered.

A dark violet solid was obtained. The NMR and mass spectra were inaccordance with compound 7.

Step 2

Compounds 2 and 7,1,3-dimethyl-3,4,5,6-tetrahydro-2(1H)-pyrimidinone (4ml) and a catalytic amount of KI were placed in a three-necked flask.

The mixture was stirred at 95° C. for 14 hours.

The product was precipitated from ethyl acetate and then filtered off.The precipitate was washed several times with dichloromethane. Compound8 was recovered in the form of a matte dark purple powder.

Dyeing Example

The process was performed as in example 1.

A strong dark purple shade was obtained with compound 8.

1. A cationic compound of formula (I):Dye1-LK-Dye2.   (I) or the addition salts thereof with an acid, theelectrical neutrality of the compound is ensured by at least onecosmetically acceptable anion An, wherein: Dye1 and Dye2 are such thatthe compound of formula (I) is not symmetrical, and are chosen from:

wherein: W₁ and W₆, which may be identical or different, are each chosenfrom —NR₁— and —O—, wherein R₁ is chosen from a hydrogen atom, andsaturated and unsaturated, aromatic and non-aromatic, optionallysubstituted C₁-C₂₀ hydrocarbon-based chains, which may form at least oneoptionally substituted 3- to 7-membered carbon-based ring, optionallyinterrupted with at least one hetero atom or with at least one groupbearing at least one hetero atom; wherein R₁ may form with all or partof the group LK and with the nitrogen atom to which each is attached atleast one cationic and non-cationic, saturated and unsaturated, aromaticand non-aromatic, optionally substituted 5- to 7-membered heterocycle;W′₁ and W′₆, which may be identical or different, are each chosen from—NR′₁R′₂ and —OR′₃, wherein R′₁, R′₂ and R′₃, which may be identical ordifferent, are each-chosen from ahydrogen atom and saturated andunsaturated, aromatic and non-aromatic, optionally substituted C₁-C₂₀hydrocarbon-based chains, which may form at least one optionallysubstituted 3- to 7-membered carbon-based ring, optionally interruptedwith at least one hetero atom or with at least one group bearing atleast one hetero atom; R′₁ and R′₂ optionally forming, with the nitrogenatom to which they are attached, an optionally substituted 5- or7-membered heterocycle optionally comprising another nitrogen ornon-nitrogen hetero atom; wherein R′₁, R′₂ and R′₃, together orseparately, may form, with all or part of the group LK and with thenitrogen or oxygen atom to which each is attached, at least one cationicand-non-cationic, saturated and unsaturated, aromatic and non-aromatic,optionally substituted 5- to 7-membered heterocycle; W₂, W₅, W′₂ andW′₅, which may be identical or different, are each chosen from:

wherein: X, is chosen from a nitrogen atom and CR₇; X₂ is chosen from anitrogen atom and CR₈; Z₁ is chosen from a nitrogen atom and CR₁₀; Z₂ ischosen from a nitrogen atom and CR₁₁; R₄, R₅, R₆, R′₆, R₇, R₈, R₁₀ andR₁₁, which may be identical or different, are chosen from: a hydrogenatom linear and branched, saturated and unsaturated, aromatic andnon-aromatic, optionally substituted C₁-C₁₆ hydrocarbon-based chains,which may form at least one optionally substituted 3- to 6-memberedcarbon-based ring, optionally interrupted with at least one hetero atomor with at least one group bearing at least one hetero atom; a hydroxylgroup, a C₁-C₄ alkoxy group, a C₂-C₄ (poly)hydroxyalkoxy group; analkoxycarbonyl group (RO—CO—) wherein R is chosen from a C₁-C₄ alkylradical, and an alkylcarbonyloxy radical (RCO—O—) wherein R is chosenfrom a C₁-C₄ alkyl radical; an amino group, an amino group substitutedwith at least one C₁-C₄ alkyl radicals, which may be identical ordifferent, optionally bearing at least one hydroxyl group, the at leastone alkyl radical optionally forming, with the nitrogen atom to which itis attached, a 5- or 6-membered heterocycle optionally bearing anothernitrogen or non-nitrogen hetero atom; an alkylcarbonylamino group(RCO—NR—) wherein R, which may be identical or different, are eachchosen from a C₁-C₄ alkyl radical; a carbamoyl group ((R)₂N—CO) whereinR, which may be identical or different, are chosen from a hydrogen atomand a C₁-C₄ alkyl radical; a ureido group (N(R)₂—CO—NR′—) wherein R andR′, which may be identical or different, are each chosen from a hydrogenatom and a C₁-C₄ alkyl radical; a sulfonamide group ((R)₂N—SO₂—) whereinR, which may be identical or different, are each chosen from a hydrogenatom and a C₁-C₄ alkyl radical; an alkylsulfonylamino group (RSO₂—NR′—)wherein R and R′, which may be identical or different, are each chosenfrom a hydrogen atom and a C₁-C₄ alkyl radical; a guanidinium group((R′)₂N—C(═NH₂ ⁺)—NR—) wherein R and R′, which may be identical ordifferent, are each chosen from a hydrogen atom and a C₁-C₄ alkylradical; a nitro group; a cyano group; a halogen atom; R₄, R₅, R₆, R′₆,R₇, R₈, R₁₀ and R₁₁, which may be identical or different, may optionallyform, with all or some of the groups W′₁ or W′₆, saturated andunsaturated, aromatic and non-aromatic, optionally substituted 5- to7-membered heterocycles; a bond from W′₂ to W′₁ or to the group LK, orfrom W′₅ to W′₆ or to the group LK; a is the bond from W₂, W₅, W′₂ orW′₅ to the azo group —N═N—; b is the bond from W₂ to W₁, from W₅ to W₆,from W′₂ to W′₁ or to the group: LK, or from W′₅ to W′₆ or to the groupLK; R₉ is chosen from: a hydrogen atom, linear and branched, saturatedand unsaturated, aromatic and non-aromatic, optionally substitutedC₁-C₁₆ hydrocarbon-based chains, which may form at least one optionallysubstituted 3- to 7-membered carbon-based ring, n and n′, which may beidentical or different, are chosen from integers, wherein their sum isless than or equal to 6; W₃ and W₄, which may be identical or different,are each chosen from cationic heteroaromatic radicals chosen from:

wherein R′₄, which may be identical or different, are chosen from:linear and branched, saturated and unsaturated, aromatic andnon-aromatic, optionally substituted C₁-C₁₆ hydrocarbon-based chains,which may form at least one 3- to 6-membered carbon-based ring,optionally interrupted with at least one hetero atom or with at leastone group bearing at least one hetero atom; a hydroxyl group, a C₁-C₄alkoxy group a C₂-C₄ (poly)hydroxyalkoxy group; an alkoxycarbonyl group(RO—CO—) wherein R is chosen from a C₁-C₄ alkyl radical and analkylcarbonyloxy radical (RCO—O—) wherein R is chosen from a C₁-C₄ alkylradical; an amino group; an amino group substituted with at least oneC₁-C₄ alkyl radical, which may be identical or different, optionallybearing at least one hydroxyl group, the at least one alkyl radicaloptionally forming, with the nitrogen atom to which they are attached, a5- or 6-membered heterocycle optionally bearing another nitrogen ornon-nitrogen hetero atom; an alkylcarbonylamino group (RCO—NR′—) whereinR is chosen from a C₁-C₄ alkyl radical and R′ is chosen from a hydrogenatom and a C₁-C₄ alkyl radical; a carbamoyl group ((R)₂N—CO—) wherein R,which may be identical or different, are chosen from a hydrogen atom ora C₁-C₄ alkyl radical; a ureido group (N(R)₂—CO—NR′—) wherein R and R′,which may be identical or different, are each chosen from a hydrogenatom and a C₁-C₄ alkyl radical; a sulfonamide group ((R)₂N—SO₂—) whereinR, which may be identical or different, are each chosen from a hydrogenatom and a C₁-C₄ alkyl radical; an alkylsulfonylamino group (RSO₂—NR′—)wherein R and R′, which may be identical or different, are each chosenfrom a hydrogen atom and a C₁-C₄ alkyl radical;a guanidinium group((R′)₂N—C(═NH₂ ⁺)—NR—) wherein R and R′, which may be identical ordifferent, are each chosen from a hydrogen atom and a C₁-C₄ alkylradical; a nitro group; a cyano group; a halogen atom; wherein tworadicals R′₄ borne by two adjacent carbon atoms of a main ring mayoptionally form an aromatic or non-aromatic, 5- or 6-membered secondaryring, optionally substituted with at least one group chosen from ahydrogen atom; hydroxyl groups; C₁-C₄ alkyl radicals; C₁-C₄ alkoxyradicals; C₂-C₄(poly)hydroxyalkoxy radicals; amino radicals; aminoradicals substituted with at least one C₁-C₄ alkyl radical, which may beidentical or different, optionally bearing at least one hydroxyl group;R′₅ is chosen from linear and branched, saturated and unsaturated,aromatic and non-aromatic, optionally substituted Cl-C₁₆hydrocarbon-based chains, which may form at least one optionallysubstituted 3- to 6-membered carbon-based ring, optionally interruptedwith at least one hetero atom or with at least one group bearing atleast one hetero atom; wherein R′₅ is such that the atom directly linkedto the quaternized nitrogen atom is a carbon atom; R′₇ is chosen from anoptionally substituted C₁-C₄ alkyl radical; an optionally substitutedphenyl radical; and an optionally substituted benzyl radical; the bond clinks the cationic radical defined by formulae (1) to (11) to the azogroup; wherein said bond may be on the main or secondary ring; p is annumber ranging from 0 to 4, p′ is an number ranging from 0 to 2 and p″is an number ranging from 0 to 3; wherein the main ring does not bearthe maximum number of substituents, each unsubstituted position bears anitrogen atom; LK is chosen from saturated and unsaturated, linear andbranched, cyclic and non-cyclic, aromatic and non-aromatic, optionallysubstituted C₂-C₄₀ hydrocarbon-based chains, bearing at least onecationic charge, optionally interrupted with at least one hetero atom orgroup comprising at least one hetero atom; wherein LK may end with ahetero atom or group bearing at least one hetero atom if LK is linked toW′₂ or W′₅; and wherein, LK may end with a group bearing at least onehetero atom chosen from —CO— and —SO₂— if LK is linked to W₆ or W₁.
 2. Acompound according to claim 1, wherein R₁, R′₁, R′₂ and R′₃, which maybe identical or different, are chosen from: a hydrogen atom; optionallysubstituted C₁-C₆ alkyl radicals; aryl and arylalkyl radicals, whereinthe aryl is optionally substituted; wherein R₁ may form with all or partof the group LK and with the nitrogen atom to which each is attached, asaturated and unsaturated, aromatic and non-aromatic, optionallysubstituted 5- to 7-membered heterocycle; wherein R′₁, R′₂ or R′₃,together or separately, may form, with all or part of the group LK andwith the nitrogen or oxygen atom to which each is attached, a saturatedand unsaturated, aromatic and non-aromatic, optionally substituted 5- to7-membered heterocycle.
 3. A compound according to claim 2, wherein thearyl and arylalkyl radicals, wherein the aryl is optionally substitutedis chosen from phenyl and benzyl.
 4. A compound according to claim 2,wherein R₁, R′₁, R′₂ and R′₃, which may be identical or different, arechosen from: a hydrogen atom; optionally substituted C₁-C₃ alkylradicals; a phenyl radical, optionally substituted with at least oneradical chosen from hydroxyl, C₁-C₂ alkoxy; and amino radicals and aminoradicals substituted with at least one C₁-C₄ group optionally bearing atleast one hydroxyl group; wherein R₁ or R′₂ and R′₃, together orseparately, may form, with the nitrogen, or oxygen atom for R′₃, towhich each is attached and all or part of the group LK, a 5- to7-membered heterocycle chosen from pyrrolidines, piperidines,piperazines and homopiperazines optionally substituted with at least oneradical chosen from methyl, hydroxyl, amino and (di)methylaminoradicals.
 5. A compound according to claim 4, wherein the optionallysusbstituted C₁-C₃ alkyl radical is chosen from methyl, ethyl;2-hydroxyethyl or 2-methoxyethyl.
 6. A compound according to claim 1,wherein R₁, R′₁, R′₂ and R′₃, which may be identical or different, arechosen from: a hydrogen atom; ethyl, ethyl or 2-hydroxyethyl radicals;and a phenyl radical, optionally substituted with radicals chosen fromhydroxyl, methoxy, amino, (di)methylamino and (di)(2-hydroxyethyl)aminoradicals; wherein R₁ or R′₂ and R′₃, together or separately, may form,with the nitrogen, or oxygen atom for R′₃, to which each is attached andall or part of the group LK, a 5- to 7-membered heterocycle chosen frompyrrolidine, 3-hydroxypyrrolidine, 3-dimethylaminopyrrolidine,piperidine, 2-(2-hydroxyethylpiperidine), 4-(aminomethyl)piperidine,4-(2-hydroxyethyl)piperidine, 4-(dimethylamino)-piperidine, piperazine,1-methylpiperazine, 1-(2-hydroxyethyl)piperazine,1-(2-aminoethyl)piperazine, 1-hydroxyethylethoxypiperazine,homopiperazine and 1-methyl-1,4-perhydrodiazepine.
 7. A compoundaccording to claim 1, wherein R₄, R₅, R₆, R′₆, R₇, R₈, R₁₀ and R₁₁,which may be identical or different, are chosen from: a hydrogen atomfor R₄, R₅, R₇, R₈, R₁₀ and R₁₁; an optionally substituted C₁-C₁₆ alkylradical; a halogen atom; a hydroxyl group; a C₁-C₂ alkoxy radical; aC₂-C₄ (poly)hydroxyalkoxy radical; an amino radical; an amino radicalsubstituted with one or two C₁-C₄ alkyl radicals, which may be identicalor different, optionally bearing at least one group chosen from hydroxyland C₁-C₄ dialkylamino groups; an alkylcarbonylamino radical (RCO—NR′—)wherein R is chosen from a C₁-C₄ alkyl radical and R′ is chosen from ahydrogen and a C₁-C₄ alkyl radical; a carbamoyl radical ((R)₂N—CO—)wherein R, which may be identical or different, are each chosen from ahydrogen atom and a C₁-C₄ alkyl radical optionally bearing at least onehydroxyl group; an alkylsulfonylamino radical (R′SO₂—NR—) wherein R ischosen from a hydrogen atom and a C₁-C₄ alkyl radical optionally bearingat least one hydroxyl group, and R′ is chosen from a C₁-C₄ alkylradical; an aminosulfonyl radical ((R)₂N—SO₂—) wherein R, which may beidentical or different, are each chosen from a hydrogen atom and a C₁-C₄alkyl radical optionally bearing at least one hydroxyl group; and a bondfrom W′₂ to W′₁ or to the group LK, or from W′₅ to W′₆ or to the groupLK.
 8. A compound according to claim 1, wherein R₄, R₅, R₆, R′₆, R₇, R₈,R₁₀ and R₁₁, which may be identical or different, are chosen from: ahydrogen atom for R₄, R₅, R₆, R′₆, R₇, R₈, R₁₀ and R₁₁; a C₁-C₄ alkylradical optionally substituted with at least one radical chosen fromhydroxyl and acylamino radicals, or amino radicals substituted with twoidentical or different C₁-C₂ alkyl radicals, optionally bearing at leastone hydroxyl group, or a C₁-C₂ alkoxy radical; an amino radical; anamino radical substituted with one or two identical or different C₁-C₂alkyl radicals, optionally bearing at least one hydroxyl group; anacylamino radical; a carbamoyl radical; a sulfonylamino radical; ahydroxyl radical; a C₁-C₂ alkoxy radical; and bonds from W′₂ to W′₁ orto the group LK, or from W′₅ to W′₆ or to the group LK.
 9. A compoundaccording to claim 1, wherein R₉ is chosen from a hydrogen ato; a C₁-C₁₅alkyl radical; a C₂-C₆ monohydroxyalkyl radical; aC₂-C₆-polyhydroxyalkyl radical; a (C₁-C₆)alkoxy(C₂-C₆)alkyl radical; anoptionally substituted aryl radical; an optionally substituted arylalkylradical; a C₂-C₆ aminoalkyl radical; and a C₂-C₆ aminoalkyl radical, theamine of which is substituted with two identical or different,optionally substituted C₁-C₄ alkyl radicals; wherein R₉ is such that theatom directly linked to the nitrogen atom is a carbon atom.
 10. Acompound according to claim 9, wherein R₉ is chosen from a hydrogenatom; a C₁-C₆ alkyl radical; a C₂-C₆ monohydroxyalkyl radical; a C₂-C₆polyhydroxyalkyl radical; a (C₁-C₆)alkoxy(C₂-C₆)alkyl radical; a phenylradical optionally substituted with a group chosen from at least onechlorine atom, a hydroxyl group, a group RCO—NH— wherein R is chosenfrom a C₁-C₄ alkyl radical and an amino radical substituted with twoidentical or different C₁-C₄ alkyl radicals; a benzyl radical; a C₁-C₆aminoalkyl radical; and a C₁-C₆ aminoalkyl radical wherein the amine issubstituted with two identical or different C₁-C₄ alkyl radicals;wherein R₉ is such that the atom directly linked to the nitrogen atom isa carbon atom.
 11. A compound according to claim 1, wherein W₂, W₅, W′₂and W′₅, which may be identical or different, are each chosen fromcompound of formula (a) or (c).
 12. A compound according to claim 1,wherein X₁ is chosen from CR₇.
 13. A compound according to claim 1,wherein X₂ is chosen from CR₈.
 14. A compound according to claim 1,wherein W₃ and W₄, which may be identical or different, are each chosenfrom:

wherein R′₄, R′₅, R′₇, p, p′ and c are as defined in claim
 1. 15. Acompound according to claim 14, wherein the aromatic heterocycle ischosen from 2-imidazolium, 2-benzimidazolium, 2-pyridinium,3-pyridinium, 4-pyridinium, 2-quinolinium, 4-quinolinium, 3-pyrazolium,4-pyrazolium, 3-indazolium, 4-indazolium, 5-indazolium, 6-indazolium and7-indazolium; wherein at least one of the two groups W₃ or W₄ is notchosen from an unsubstituted imidazolium group.
 16. A compound accordingto claim 1, wherein LK is chosen from the following formula:

wherein D and D′, which may be identical or different, are each chosenfrom linear and branched, saturated and unsaturated C₁-C₁₄hydrocarbon-based groups, optionally interrupted with at least onehetero atom or with at least one group bearing at least one hetero atom;the bond d links the arms D and D′ to the groups W₁, W₆, W′₂ and W′₅; qis greater than or equal to 1; R is chosen from

wherein R₁₂, R₁₃, R′₁₂ and R′₁₃, which may be identical or different,are each chosen from a C₁-C₁₅ alkyl radical; a C₁-C₆ monohydroxyalkylradical; a C₂-C₆ polyhydroxyalkyl radical; a (C₁-C₆)alkoxy(C₁-C₆)alkylradical; an aryl radical; an arylalkyl radical; a C₁-C₆ amidoalkylradical; a C₁-C₆ aminoalkyl radical; and a C₁-C₆ aminoalkyl radicalwherein the amine is substituted with at least one group, which may beidentical or different, chosen from C₁-C₄ alkyl, (C₁-C₆)alkylcarbonyl,acylamino and (C₁-C₆)alkylsulfonyl radicals; R₁₂ and R₁₃ may form,together with the nitrogen atom to which they are attached, a 5-, 6- or7-membered saturated cationic ring that may comprise at least one heteroatom, the cationic ring optionally is substituted with group :chosenfrom a halogen atom, a hydroxyl radical, a C₁-C₆ alkyl radical, a C₁-C₆monohydroxyalkyl radical, a C₂-C₆ polyhydroxyalkyl radical, a C₁-C₆alkoxy radical, an amido radical, a (C₁-C₆)alkylcarbonyl radical, a thioradical, a C₁-C₆ thioalkyl radical, a (C₁-C₆)alkylthio radical, an aminoradical and an amino radical substituted- with at least one group, whichmay be identical or different, chosen from C₁-C₆ alkyl,(C₁-C₆)alkylcarbonyl, acylamino or (C₁-C₆)alkylsulfonyl radicals; R₁₂ orR₁₃ may form, with D or D′, a 5-, 6- or 7-membered saturated cationicring that may comprise at least one hetero atom, the cationic ringoptionally is substituted with a group chosen from a halogen atom, ahydroxyl radical, a C₁-C₆ alkyl radical, a C₁-C₆ monohydroxyalkylradical, a C₂-C₆ polyhydroxyalkyl radical, a C₁-C₆ alkoxy radical, anamido radical, a (C₁-C₆)alkylcarbonyl radical, a thio radical, a C₁-C₆thioalkyl radical, a (C₁-C₆)alkylthio radical, an amino radical and anamino radical substituted with at least one group, which may beidentical or different, chosen from C₁-C₆ alkyl, (C₁-C₆)alkylcarbonyl,acylamino or (C₁-C₆)alkylsulfonyl radicals; R₁₂ and R₁₃ may form with W₁or W₆ a 5-, 6- or 7-membered, saturated and unsaturated, aromatic andnon-aromatic, optionally substituted cationic heterocycle; the ringmembers E, G, J and L, which may be identical or different, are eachchosen from carbon, oxygen, sulfur or nitrogen atom to form a ringchosen from pyrazolium, imidazolium, triazolium, oxazolium, isoxazolium,thiazolium or isothiazolium rings, R₁₄ has the same meaning as R₁₂; R₁₅is chosen from a C₁-C₆ alkyl radical; a C₁-C₆ monohydroxyalkyl radical,a C₂-C₆ polyhydroxyalkyl radical, a (C₁-C₆)alkoxy(C₁-C₆)alkyl radical, aC₂-C₆ carbamylalkyl radical, a (C₁-C₆)alkylcarboxy(C₁-C₆)alkyl radicaland a benzyl radical; wherein R₁₅ is attached to a nitrogen atom, R₁₆,which may be identical or different, are each chosen from a hydrogenatom, halogen atom, a C₁-C₆ alkyl radical, a C₁-C₆ monohydroxyalkylradical, a C₂-C₆ polyhydroxyalkyl radical, a C₁-C₆ alkoxy radical, anamido radical, a carboxyl radical, a C₁-C₆ alkylcarbonyl radical, aC₁-C₆ thioalkyl radical, a (C₁-C₆)alkylthio radical, an amino radicaldisubstituted with a (C₁-C₆)alkyl, (C₁-C₆)alkylcarbonyl or(C₁-C₆)alkylsulfonyl radical, a benzyl radical, and a phenyl radicaloptionally substituted with at least one radicals chosen from methyl,hydroxyl, amino and methoxy radicals, wherein R₁₆ is attahced to acarbon atom, An is chosen from an organic or mineral anion; z is anumber ranging from 1 to 3; y is a number ranging from 0 to 1; v is anumber ranging from 1 to 2; x is a number ranging from 0 to 1; when x=0,then one of the linker arms D or D′ is attached to the quaternizednitrogen atom, and when x=1, at least one of the linker arms D and/or D′is attached to a carbon atom.
 17. A compound according to claim 16,wherein q is equal to 1 or
 2. 18. A compound according to claim 16,wherein, in formula (d), R₁₂ and R₁₃, which may be identical ordifferent, are chosen from a C₁-C₆ alkyl radical, a C₁-C₄monohydroxyalkyl radical, a C₂-C₄ polyhydroxyalkyl radical, a(C₁-C₆)alkoxy(C₂-C₄)alkyl radical, a C₂-C₆ amidoalkyl radical and aC₂-C₆ dimethylaminoalkyl radical.
 19. A compound according to claim 18,wherein D and D′, which may be identical or different, are chosen from aC₁-C₆ alkyl chain that is optionally substituted.
 20. A compoundaccording to claim 16, wherein, in formula (e), the ring members E, G, Jand L form a ring chosen from imidazolium, pyrazolium, oxazolium orthiazolium rings; and wherein x and b are equal to
 0. 21. A compoundaccording to claim 20, wherein D and D′, which may be identical ordifferent, are each chosen from a C₁-C₄ alkyl chain that may besubstituted.
 22. A compound according to claim 20, wherein R₁₄ is chosenfrom a methyl, ethyl or 2-hydroxyethyl radical.
 23. A compound accordingto claim 16, wherein, in formula (f), R′₁₂ and R′₁₃, which may beidentical or different, are chosen from a C₁-C₆ alkyl radical, a C₁-C₄monohydroxyalkyl radical, a C₂-C₄ polyhydroxyalkyl radical, a(C₁-C₆)alkoxy(C₂-C₄)alkyl radical, a C₂-C₆ amidoalkyl radical and aC₂-C₆ dimethylaminoalkyl radical.
 24. A compound according to claim 23,wherein D and D′, which may be identical or different, are chosen from aC₁-C₆ alkyl chain that may be substituted.
 25. A compound according toclaim 16, wherein the coefficient v is equal to
 1. 26. A compoundaccording to claim 1, wherein the formula (I) compounds are chosen from:

wherein: R₁, R₃, R₄, R₁₂, R₁₃, R′₄, R′₅, R′₇, R′₁₂, R′₁₃, p and p′ areas defined in claim 1; r and r′, which may be identical or different,are numbers ranging from 1 to 10; wherein the electrical neutrality ofthe molecule is respected by the presence of at least one cosmeticallyacceptable anion An, as defined in claim
 1. 27. A compound according toclaim 1, wherein the cosmetically acceptable anion is chosen fromhalides; hydroxides; sulfates; hydrogen sulfates; (C₁-C₆)alkyl sulfates;phosphates; carbonates; hydrogen carbonates; perchlorates; acetates;tartrates; citrates; oxalates; (C₁-C₆)alkylsulfonates; arylsulfonates,which are unsubstituted or substituted with a C₁-C₄ alkyl radical.
 28. Acompound according to claim 27, wherein the arylsulfonate is4-tolylsulfonate.
 29. A dye composition comprising, in a medium that issuitable for dyeing keratin fibers, as direct dye, at least one compoundof formula (I):Dye1-LK-Dye2   (I) or the addition salts thereof with an acid, theelectrical neutrality of the compound is ensured by at least onecosmetically acceptable anion An, wherein: Dye1 and Dye2 are such-thatthe compound of formula (I) is not symmetrical, and are chosen from:

wherein: W₁ and W₆, which may be identical or different, are each chosenfrom —NR₁— and —O—, wherein R₁ is chosen from a hydrogen atom, andsaturated and unsaturated, aromatic and non-aromatic, optionallysubstituted C₁-C₂₀ hydrocarbon-based chains, which may form at least oneoptionally substituted 3- to 7-membered carbon-based ring, optionallyinterrupted with at least one hetero atom or with at least one groupbearing at least one hetero atom; wherein R₁ may form with all or partof the group LK and with the nitrogen atom to which each is attached atleast one cationic and non-cationic, saturated and unsaturated, aromaticand non-aromatic, optionally substituted 5- to 7-membered heterocycle;W′₁ and W′₆, which may be identical or different, are each chosen from—NR′₁R′₂ and —OR′₃, wherein R′₁, R′₂ and R′₃, which may be identical ordifferent, are each chosen from ahydrogen atom and saturated andunsaturated, aromatic and non-aromatic, optionally substituted C₁-C₂₀hydrocarbon-based chains, which may form at least one optionallysubstituted 3- to 7-membered carbon-based ring, optionally interruptedwith at least one hetero atom or with at least one group bearing atleast one hetero atom; R′₁ and R′₂ optionally forming, with the nitrogenatom to which they are attached, an optionally substituted 5- or7-membered heterocycle optionally comprising another nitrogen ornon-nitrogen hetero atom; wherein R′₁, R′₂ and R′₃, together orseparately, may form, with all or part of the group LK and with thenitrogen or oxygen atom to which each is attached, at least one cationicand non-cationic, saturated and unsaturated, aromatic and non-aromatic,optionally substituted 5- to 7-membered heterocycle; W₂, W₅, W′₂ andW′₅, which may be identical or different, are each chosen from:

wherein: X₁ is chosen from a nitrogen atom and CR₇; X₂ is chosen from anitrogen atom and CR₈; Z₁ is chosen from a nitrogen atom and CR₁₀; Z₂ ischosen from a nitrogen atom and CR₁₁; R₄, R₅, R₆, R′₆, R₇, R₈, R₁₀ andR₁₁, which may be identical or different, are chosen from: a hydrogenatom linear and branched, saturated and unsaturated, aromatic andnon-aromatic, optionally substituted C₁-C₁₆ hydrocarbon-based chains,which may form at least one optionally substituted 3- to 6-memberedcarbon-based ring, optionally interrupted with at least one hetero atomor with at least one group bearing at least one hetero atom; a hydroxylgroup, a C₁-C₄ alkoxy group, a C₂-C₄ (poly)hydroxyalkoxy group; analkoxycarbonyl group (RO—CO—) wherein R is chosen from a C₁-C₄ alkylradical, and an alkylcarbonyloxy radical (RCO—O—) wherein R is chosenfrom a C₁-C₄ alkyl radical; an amino group, an amino group substitutedwith at least one C₁-C₄ alkyl radicals, which may be identical ordifferent, optionally bearing at least one hydroxyl group, the at leastone alkyl radical optionally forming, with the nitrogen atom to which itis attached, a 5- or 6-membered heterocycle optionally bearing anothernitrogen or non-nitrogen hetero atom; an alkylcarbonylamino group(RCO—NR—) wherein R, which may be identical or different, are eachchosen from a C₁-C₄ alkyl radical; a carbamoyl group ((R)₂N—CO) whereinR, which may be identical or different, are chosen from a hydrogen atomand a C₁-C₄ alkyl radical; a ureido group (N(R)₂—CO—NR′—) wherein R andR′, which may be identical or different, are each chosen from a hydrogenatom and a C₁-C₄ alkyl radical; a sulfonamide group ((R)₂N—SO₂—) whereinR, which may be identical or different, are each chosen from a hydrogenatom and a C₁-C₄ alkyl radical; an alkylsulfonylamino group (RSO₂—NR′—)wherein R and R′, which may be identical or different, are each chosenfrom a hydrogen atom and a C₁-C₄ alkyl radical; a guanidinium group((R′)₂N—C(═NH₂ ⁺)—NR—) wherein R and R′, which may be identical ordifferent, are each chosen from a hydrogen atom and a C₁-C₄ alkylradical; a nitro group; a cyano group; a halogen atom; R₄, R₅, R₆, R′₆,R₇, R₈, R₁₀ and R₁₁, which may be identical or different, may optionallyform, with all or some of the groups W′₁ or W′₆, saturated andunsaturated, aromatic and non-aromatic, optionally substituted 5- to7-membered heterocycles; a bond from W′₂ to W′₁ or to the group LK, orfrom W′₅ to W′₆ or to the group LK; a is the bond from W₂, W₅, W′₂ orW′₅ to the azo group —N═N—; b is the bond from W₂ to W₁, from W₅ to W₆,from W′₂ to W′₁ or to the group LK, or from W′₅ to W′₆ or to the groupLK; R₉ is chosen from: a hydrogen atom, linear and branched, saturatedand unsaturated, aromatic and non-aromatic, optionally substitutedC₁-C₁₆ hydrocarbon-based chains, which may form at least one optionallysubstituted 3- to 7-membered carbon-based ring, n and n′, which may beidentical or different, are chosen from integers, wherein their sum isless than or equal to 6; W₃ and W₄, which may be identical or different,are each chosen from cationic heteroaromatic radicals chosen from:

wherein R′₄, which may be identical or different, are chosen from:linear and branched, saturated and unsaturated, aromatic andnon-aromatic, optionally substituted C₁-C₁₆hydrocarbon-based chains,which may form at least one 3- to 6-membered carbon-based ring,optionally interrupted with at least one hetero atom or with at leastone group bearing at least one hetero atom; a hydroxyl group, a C₁-C₄alkoxy group a C₂-C₄ (poly)hydroxyalkoxy group; an alkoxycarbonyl group(RO—CO—) wherein R is chosen from a C₁-C₄ alkyl radical and analkylcarbonyloxy radical (RCO—O—) wherein R is chosen from a C₁-C₄ alkylradical; an amino group; an amino group substituted with at least oneC₁-C₄ alkyl radical, which may be identical or different, optionallybearing at least one hydroxyl group, the at least one alkyl radicaloptionally forming, with the nitrogen atom to which they are attached, a5- or 6-membered heterocycle optionally bearing another nitrogen ornon-nitrogen hetero atom; an alkylcarbonylamino group (RCO—NR′—) whereinR is chosen from a C₁-C₄ alkyl radical and R′ is chosen from a hydrogenatom and a C₁-C₄ alkyl radical; a carbamoyl group ((R)₂N—CO—) wherein R,which may be identical or different, are chosen from a hydrogen atom ora C₁-C₄ alkyl radical; a ureido group (N(R)₂—CO—NR′—) wherein R and R′,which may be identical or different, are each chosen from a hydrogenatom and a C₁-C₄ alkyl radical; a sulfonamide group ((R)₂N—SO₂—) whereinR, which may be identical or different, are each chosen from a hydrogenatom and a C₁-C₄ alkyl radical; an alkylsulfonylamino group (RSO₂—NR′—)wherein R and R′, which may be identical or different, are each chosenfrom a hydrogen atom and a C₁-C₄ alkyl radical; a guanidinium group((R′)₂N—C(═NH₂ ⁺)—NR—) wherein R and R′, which may be identical ordifferent, are each chosen from a hydrogen atom and a C₁-C₄ alkylradical; a nitro group; a cyano group; a halogen atom; wherein tworadicals R′₄-borne by two adjacent carbon atoms of a main ring mayoptionally form an aromatic or non-aromatic, 5- or 6-membered secondaryring, optionally substituted with at least one group chosen from ahydrogen atom; hydroxyl groups; C₁-C₄ alkyl radicals; C₁-C₄ alkoxyradicals; C₂-C₄(poly)hydroxyalkoxy radicals; amino radicals; aminoradicals substituted with at least one C₁-C₄ alkyl radical, which may beidentical or different, optionally bearing at least one hydroxyl group;R′₅ is chosen from linear and branched, saturated and unsaturated,aromatic and non-aromatic, optionally substituted C₁-C₁₆hydrocarbon-based chains, which may form at least oneoptionally-substituted 3- to 6-membered carbon-based ring, optionallyinterrupted with at least one hetero atom or with at least one groupbearing at least one hetero atom; wherein R′₅ is such that the atomdirectly linked to the quaternized nitrogen atom is a carbon atom; R′₇is chosen from an optionally substituted C₁-C₄ alkyl radical; anoptionally substituted phenyl radical; and an optionally substitutedbenzyl radical; the bond c links the cationic radical defined byformulae (1) to (11) to the azo group; wherein said bond may be on themain or secondary ring; p is an number ranging from 0 to 4, p′ is annumber ranging from 0 to 2 and p″ is an number ranging from 0 to 3;wherein the main ring does not bear the maximum number of substituents,each unsubstituted position bears a nitrogen atom; LK is chosen fromsaturated and unsaturated, linear and branched, cyclic and non-cyclic,aromatic and non-aromatic, optionally substituted C₂-C₄₀hydrocarbon-based chains, bearing at least one cationic charge,optionally interrupted with at least one hetero atom or group comprisingat least one hetero atom; wherein LK may end with a hetero atom or groupbearing-at least one hetero atom if LK is linked to W′₂ or W′₅; andwherein LK may end with a group bearing at least one hetero atom chosenfrom —CO— and —SO₂— if LK is linked to W₆ or W₁.
 30. A compositionaccording to claim 29, wherein the at least one compound of formula (I)is present in an amount ranging from 0.001% to 20% by weight, relativeto the total weight of the dye composition.
 31. A composition accordingto claim 30, wherein the at least one compound of formula (I) is presentin an amount ranging from 0.01% to 10% by weight, relative to the totalweight of the dye composition.
 32. A composition according to claim 29,comprising at least one additional direct dye, and at least oneoxidation base optionally combined with at least one coupler, ormixtures thereof.
 33. A composition according to claim 32, wherein theadditional direct dye is a cationic or nonionic dye chosen fromnitrobenzene dyes, azo, azomethine, methine, tetraazapentamethine,anthraquinone, naphthoquinone, benzoquinone, phenothiazine, indigoid,xanthene, phenanthridine, phthalocyanin and triarylmethane-based dyesand natural dyes.
 34. A composition according to claim 32, wherein theoxidation base is chosen from o-phenylenediamines, p-phenylenediamines,double bases, o-aminophenols, p-aminophenols and heterocyclic bases, theaddition salts thereof with an acid.
 35. A composition according toclaim 32, wherein the coupler is chosen from m-aminophenols,m-phenylenediamines, m-diphenols, naphthols and heterocyclic couplers,the addition salts thereof with an acid, and also mixtures thereof. 36.A composition according to claim 29, wherein it comprises at least oneoxidizing agent.
 37. A process for dyeing keratin fibers, comprisingplacing at least one composition comprising, in a medium that issuitable for dyeing keratin fibers, as direct dye, at least one compoundof formula (I):Dye1-LK-Dye2   (I) or the addition salts thereof with an acid, theelectrical neutrality of the compound is ensured by at least onecosmetically acceptable anion An, wherein: Dye1 and Dye2 are such thatthe compound of formula (I) is not symmetrical, and are chosen from:

wherein: W₁ and W₆, which may be identical or different, are each chosenfrom —NR₁— and —O—, wherein R₁ is chosen from a hydrogen atom, andsaturated and unsaturated, aromatic and non-aromatic, optionallysubstituted C₁-C₂₀ hydrocarbon-based chains, which may form at least oneoptionally substituted 3- to 7-membered carbon-based ring, optionallyinterrupted with at least one hetero atom or with at least one groupbearing at least one hetero atom; wherein R₁ may form with all or partof the group LK and with the nitrogen atom to which each is attached atleast one cationic and non-cationic, saturated and unsaturated, aromaticand non-aromatic, optionally substituted 5- to 7-membered heterocycle;W′₁ and W′₆, which may be identical or different, are each chosen from—NR′₁R′₂ and —OR′₃, wherein R′₁, R′₂ and R′₃, which may be identical ordifferent, are each chosen from ahydrogen atom and saturated andunsaturated, aromatic and non-aromatic, optionally substituted C₁-C₂₀hydrocarbon-based chains, which may form at least -one optionallysubstituted 3- to 7-membered carbon-based ring, optionally interruptedwith at least one hetero atom or with at least one group bearing atleast one hetero atom; R′₁ and R′₂ optionally forming, with the nitrogenatom to which they are attached, an optionally substituted 5- or7-membered heterocycle optionally comprising another nitrogen ornon-nitrogen hetero atom; wherein R′₁, R′₂ and R′₃, together orseparately, may form, with all or part of the group LK and with thenitrogen or oxygen atom to which each is attached, at least one cationicand non-cationic, saturated and unsaturated, aromatic and non-aromatic,optionally substituted 5- to 7-membered heterocycle; W₂, W₅, W′₂ andW′₅, which may be identical or different, are each chosen from:

wherein: X₁ is chosen from a nitrogen atom and CR₇; X₂ is chosen from anitrogen atom and CR₈; Z₁ is chosen from a nitrogen atom and CR₁₀; Z₂ ischosen from a nitrogen atom and CR₁₁; R₄, R₅, R₆, R′₆, —R₇, R₈, R₁₀ andR₁₁, which may be identical or different, are chosen from: a hydrogenatom linear and branched, saturated and unsaturated, aromatic andnon-aromatic, optionally substituted C₁-C₁₆ hydrocarbon-based chains,which may form at least one optionally substituted 3- to 6-memberedcarbon-based ring, optionally interrupted with at least one hetero atomor with at least one group bearing at least one hetero atom; a hydroxylgroup, a C₁-C₄ alkoxy group, a C₂-C₄ (poly)hydroxyalkoxy group; analkoxycarbonyl group (RO—CO—) wherein R is chosen from a C₁-C₄ alkylradical, and an alkylcarbonyloxy radical (RCO—O—) wherein R is chosenfrom a C₁-C₄ alkyl radical; an amino group, an amino group substitutedwith at least one C₁-C₄ alkyl radicals, which may be identical ordifferent, optionally bearing at least one hydroxyl group, the at leastone alkyl radical optionally forming, with the nitrogen atom to which itis attached, a 5- or 6-membered heterocycle optionally bearing anothernitrogen or non-nitrogen hetero atom; an alkylcarbonylamino group(RCO—NR—) wherein R, which may be identical or different, are eachchosen from a C₁-C₄ alkyl radical; a carbamoyl group ((R)₂N—CO) whereinR, which may be identical or different, are chosen from a hydrogen atomand a C₁-C₄ alkyl radical; a ureido group (N(R)₂—CO—NR′—) wherein R andR′, which may be identical or different, are each chosen from a hydrogenatom and a C₁-C₄ alkyl radical; a sulfonamide group ((R)₂N—SO₂—) whereinR, which may be identical or different, are each chosen from a hydrogenatom and a C₁-C₄ alkyl radical; an alkylsulfonylamino group (RSO₂—NR′—)wherein R and R′, which may be identical or different, are each chosenfrom a hydrogen atom and a C₁-C₄ alkyl radical; a guanidinium group((R′)₂N—C(═NH₂ ⁺)—NR—) wherein R and R′, which may be identical ordifferent, are each chosen from a hydrogen atom and a C₁-C₄ alkylradical; a nitro group; a cyano group; a halogen atom; R₄, R₅, R₆, R′₆,R₇, R₈, R₁₀ and R₁₁, which may be identical or different, may optionallyform, with all or some of the groups W′₁ or W′₆, saturated andunsaturated, aromatic and non-aromatic, optionally substituted 5- to7-membered heterocycles; a bond from W′₂ to W′₁ or to the group LK, orfrom W′₅ to W′₆ or to the group LK; a is the bond from W₂, W₅, W′₂ orW′₅ to the azo group —N═N—; b is the bond from W₂ to W₁, from W₅ to W₆,from W′₂ to W′₁ or to the group LK, or from W′₅ to W′₆ or to the groupLK; R₉ is chosen from: a hydrogen atom, linear and branched, saturatedand unsaturated, aromatic and non-aromatic, optionally substitutedC₁-C₁₆ hydrocarbon-based chains, which may form at least one optionallysubstituted 3- to 7-membered carbon-based ring, n and n′, which may beidentical or different, are chosen from integers, wherein their sum isless than or equal to 6; W₃ and W₄, which may be identical or different,are each chosen from cationic heteroaromatic radicals chosen from:

wherein R′₄, which may be identical or different, are chosen from:linear and branched, saturated and unsaturated, aromatic andnon-aromatic, optionally substituted C₁-C₁₆ hydrocarbon-based chains,which may form at least one 3- to 6-membered carbon-based ring,optionally interrupted with at least one hetero atom or with at leastone group bearing at least one hetero atom; a hydroxyl group, a C₁-C₄alkoxy group a C₂-C₄ (poly)hydroxyalkoxy group; an alkoxycarbonyl group(RO—CO—) wherein R is chosen from a C₁-C₄ alkyl radical and analkylcarbonyloxy radical (RCO—O—) wherein R is chosen from a C₁-C₄ alkylradical; an amino group; an amino group substituted with at least oneC₁-C₄ alkyl radical, which may be identical or different, optionallybearing at least one hydroxyl group, the at least one alkyl radicaloptionally forming, with the nitrogen atom to which they are attached, a5- or 6-membered heterocycle optionally bearing another nitrogen ornon-nitrogen hetero atom; an alkylcarbonylamino group (RCO—NR′—) whereinR is chosen from a C₁-C₄ alkyl radical and R′ is chosen from a hydrogenatom and a C₁-C₄ alkyl radical; a carbamoyl group ((R)₂N—CO—) wherein R,which may be identical or different, are chosen from a hydrogen atom ora C₁-C₄ alkyl radical; a ureido group (N(R)₂—CO—NR′—) wherein R and R′,which may be identical or different, are each chosen from a hydrogenatom and a C₁-C₄ alkyl radical; a sulfonamide group ((R)₂N—SO₂—) whereinR, which may be identical or different, are each chosen from a hydrogenatom and a C₁-C₄ alkyl radical; an alkylsulfonylamino group (RSO₂—NR′—)wherein R and R′, which may be identical or different, are each chosenfrom a hydrogen atom and a C₁-C₄ alkyl radical; a guanidinium group((R′)₂N—C(═NH₂ ⁺)—NR—) wherein R and R′, which may be identical ordifferent, are each chosen from a hydrogen atom and a C₁-C₄ alkylradical; a nitro group; a cyano group; a halogen atom; wherein tworadicals R′₄ borne by two adjacent carbon atoms of a main ring mayoptionally form an aromatic or non-aromatic, 5- or 6-membered secondaryring, optionally substituted with at least one group chosen from ahydrogen atom; hydroxyl groups; C₁-C₄ alkyl radicals; C₁-C₄ alkoxyradicals; C₂-C₄(poly)hydroxyalkoxy radicals; amino radicals; aminoradicals substituted with at least one C₁-C₄ alkyl radical, which may beidentical or different, optionally bearing at least one hydroxyl group;R′₅ is chosen from linear and branched, saturated and unsaturated,aromatic and non-aromatic, optionally substituted C₁-C₁₆hydrocarbon-based chains, which may form at least one optionallysubstituted 3- to 6-membered carbon-based ring, optionally interruptedwith at least one hetero atom or with at least one group bearing atleast one hetero atom; wherein R′₅ is such that the atom directly linkedto the quaternized nitrogen atom is a carbon atom; R′₇ is chosen from anoptionally substituted C₁-C₄ alkyl radical; an optionally substitutedphenyl radical; and an optionally substituted benzyl radical; the bond clinks the cationic radical defined by formulae (1) to (11) to the azogroup; wherein said bond may be on the main or secondary ring; p is annumber ranging from 0 to 4, p′ is an number ranging from 0 to 2 and p″is an number ranging from 0 to 3; herein the main ring does not bear themaximum number of substituents, each unsubstituted position bears anitrogen atom; LK is chosen from saturated and unsaturated, linear andbranched, cyclic and non-cyclic, aromatic and non-aromatic, optionallysubstituted C₂-C₄₀ hydrocarbon-based chains, bearing at least onecationic charge, optionally interrupted with at least one hetero atom orgroup comprising at least one hetero atom; wherein LK may end with ahetero atom or group bearing at least one hetero atom if LK is linked toW′₂ or W′₅; and wherein LK may end with a group bearing at least onehetero atom chosen from —CO— and —SO₂— if LK is linked to W₆ or W₁, incontact with the wet or dry fibers for a time that is sufficient toobtain the desired effect.
 38. A multi-compartment device comprising atleast one compartment comprising a composition comprising, in a mediumthat is suitable for dyeing keratin fibers, as direct dye, at least onecompound of formula (I):Dye1-LK-Dye2   (I) or the addition salts thereof with an acid, theelectrical neutrality of the compound is ensured by at least onecosmetically acceptable anion An, wherein: Dye1 and Dye2 are such thatthe compound of formula (I) is not symmetrical, and are chosen from:

wherein: W₁ and W₆, which may be identical or different, are each chosenfrom —NR₁— and —O—, wherein R₁ is chosen from a hydrogen atom, andsaturated and unsaturated, aromatic and non-aromatic, optionallysubstituted C₁-C₂₀ hydrocarbon-based chains, which may form at least oneoptionally substituted 3- to 7-membered carbon-based ring, optionallyinterrupted with at least one hetero atom or with at least one groupbearing at least one hetero atom; wherein R₁ may form with all or partof the group LK and with the nitrogen atom to which each is attached atleast one cationic and non-cationic, saturated and unsaturated, aromaticand non-aromatic, optionally substituted 5- to 7-membered heterocycle;W′₁ and W′₆, which may be identical or different, are each chosen from—NR′₁R′₂ and —OR′₃, wherein R′₁, R′₂ and R′₃, which may be identical ordifferent, are each chosen from ahydrogen atom and saturated andunsaturated, aromatic and non-aromatic, optionally substituted C₁-C₂₀hydrocarbon-based chains, which may form at least one optionallysubstituted 3- to 7-membered carbon-based ring, optionally interruptedwith at least one hetero atom or with at least one group bearing atleast one hetero atom; R′₁ and R′₂ optionally forming, with the nitrogenatom to which they are attached, an optionally substituted 5- or7-membered heterocycle optionally comprising another nitrogen ornon-nitrogen hetero atom; wherein R′₁, R′₂ and R′₃, together orseparately, may form, with all or part of the group LK and with thenitrogen or oxygen atom to which each is attached, at least one cationicand non-cationic, saturated and unsaturated, aromatic and non-aromatic,optionally substituted 5- to 7-membered heterocycle; W₂, W₅, W′₂ andW′₅, which may be identical or different, are each chosen from:

wherein: X₁ is chosen from a nitrogen atom and CR₇; X₂ is chosen from anitrogen atom and CR₈; Z₁ is chosen from a nitrogen atom and CR₁₀; Z₂ ischosen from a nitrogen atom and CR₁₁; R₄, R₅, R₆, R′₆, R₇, R₈, R₁₀ andR₁₁, which may be identical or different, are chosen from: a hydrogenatom linear and branched, saturated and unsaturated, aromatic andnon-aromatic, optionally substituted C₁-C₁₆ hydrocarbon-based chains,which may form at least one optionally substituted 3- to 6-memberedcarbon-based ring, optionally interrupted with at least one hetero atomor with at least one group bearing at least one hetero atom; a hydroxylgroup, a C₁-C₄ alkoxy group, a C₂-C₄ (poly)hydroxyalkoxy group; analkoxycarbonyl group (RO—CO—) wherein R is chosen from a C₁-C₄ alkylradical, and an alkylcarbonyloxy radical (RCO—O—) wherein R is chosenfrom a C₁-C₄ alkyl radical; an amino group, an amino group substitutedwith at least one C₁-C₄ alkyl radicals, which may be identical ordifferent, optionally bearing at least one hydroxyl group, the at leastone alkyl radical optionally forming, with the nitrogen atom to which itis attached, a 5- or-6-membered heterocycle optionally bearing anothernitrogen or non-nitrogen hetero atom; an alkylcarbonylamino group(RCO—NR—) wherein R, which may be identical or different, are eachchosen from a C₁-C₄ alkyl radical; a carbamoyl group ((R)₂N—CO) whereinR, which may be identical or different, are chosen from a hydrogen atomand a C₁-C₄ alkyl radical; a ureido group (N(R)₂—CO—NR′—) wherein R andR′, which may be identical or different, are each chosen from a hydrogenatom and a C₁-C₄ alkyl radical; a sulfonamide group ((R)₂N-S0₂-) whereinR, which may be identical or different, are each chosen from a hydrogenatom and a C₁-C₄ alkyl radical; an alkylsulfonylamino group (RSO₂—NR′—)wherein R and R′, which may be identical or different, are each chosenfrom a hydrogen atom and a C₁-C₄ alkyl radical; a guanidinium group((R′)₂N—C(═NH₂ ⁺)—NR—) wherein R and R′, which may be identical ordifferent, are each chosen from a hydrogen atom and a C₁-C₄ alkylradical; a nitro group; a cyano group; a halogen atom; R₄, R₅, R₆, R′₆,R₇, R₈, R₁₀ and R₁₁, which may be identical or different, may optionallyform, with all or some of the groups W′₁ or W′₆, saturated andunsaturated, aromatic and non-aromatic, optionally substituted 5- to7-membered heterocycles; a bond from W′₂ to W′₁ or to the group LK, orfrom W′₅ to W′₆ or to the group LK; a is the bond from W₂, W₅, W′₂ orW′₅ to the azo group —N═N—; b is the bond from W₂ to W₁, from W₅ to W₆,from W′₂ to W′₁ or to the group LK, or from W′₅ to W′₆ or to the groupLK; R₉ is chosen from: a hydrogen atom, linear and branched, saturatedand unsaturated, aromatic and non-aromatic, optionally substitutedC₁-C₁₆ hydrocarbon-based chains, which may form at least one optionallysubstituted 3- to 7-membered carbon-based ring, n and n′, which may beidentical or different, are chosen from integers, wherein their sum isless than or equal to 6; W₃ and W₄, which may be identical or different,are each chosen from cationic heteroaromatic radicals chosen from:

wherein R′₄, which may be identical or different, are chosen from:linear and branched, saturated and unsaturated, aromatic andnon-aromatic, optionally substituted C₁-C₁₆ hydrocarbon-based chains,which may form at least one 3- or 6-membered carbon-based ring,optionally interrupted with at least one hetero atom or with at leastone group bearing at least one hetero atom; a hydroxyl group, aC₁-C₄-alkoxy group a C₂-C₄ (poly)hydroxyalkoxy group; an alkoxycarbonylgroup (RO—CO—) wherein R is chosen from a C₁-C₄ alkyl radical and analkylcarbonyloxy radical (RCO—O—) wherein R is chosen from a C₁-C₄ alkylradical; an amino group; an amino group substituted with at least oneC₁-C₄ alkyl radical, which may be identical or different, optionallybearing at least one hydroxyl group, the at least one alkyl radicaloptionally forming, with the nitrogen atom to which they are attached, a5- or 6-membered heterocycle optionally bearing another nitrogen ornon-nitrogen hetero atom; an alkylcarbonylamino group (RCO—NR′—) whereinR is chosen from a C₁-C₄ alkyl radical and R′ is chosen from a hydrogenatom and a C₁-C₄ alkyl radical; a carbamoyl group ((R)₂—N—CO—) whereinR, which may be identical or different, are chosen from a hydrogen atomor a C₁-C₄ alkyl radical; a ureido group (N(R)₂—CO—NR′—) wherein R andR′, which may be identical or different, are each chosen from a hydrogenatom and a C₁-C₄ alkyl radical; a sulfonamide group ((R)₂N—SO₂—) whereinR, which may be identical or different, are each chosen from a hydrogenatom and a C₁-C₄ alkyl radical; an alkylsulfonylamino group (RSO₂—NR′—)wherein R and R′, which may be identical or different, are each chosenfrom a hydrogen atom and a C₁-C₄ alkyl radical; a guanidinium group((R′)₂N—C(═NH₂ ⁺)—NR—) wherein R and R′, which may be identical ordifferent, are each chosen from a hydrogen atom and a C₁-C₄ alkylradical; a nitro group; a cyano group; a halogen atom; wherein tworadicals R′₄ borne by two adjacent carbon atoms of a main ring mayoptionally form an aromatic or non-aromatic, 5- or 6-membered secondaryring, optionally substituted with at least one group chosen from ahydrogen atom; hydroxyl groups; C₁-C₄ alkyl radicals; C₁-C₄ alkoxyradicals; C₂-C₄(poly)hydroxyalkoxy radicals; amino radicals; aminoradicals substituted with at least one C₁-C₄ alkyl radical, which may beidentical or different, optionally bearing at least one hydroxyl group;R′₅ is chosen from linear and branched, saturated and unsaturated,aromatic and non-aromatic, optionally substituted C₁-C₁₆hydrocarbon-based chains, which may form at least one optionallysubstituted 3- to 6-membered carbon-based ring, optionally interruptedwith at least one hetero atom or with at least one group bearing atleast one hetero atom; wherein R′₅ is such that the atom directly linkedto the quaternized nitrogen atom is a carbon atom; R′₇ is chosen from anoptionally substituted C₁-C₄ alkyl radical; an optionally substitutedphenyl radical; and an optionally substituted benzyl radical; the bond clinks the cationic radical defined by formulae (1) to (11) to the azogroup; wherein said bond may be on the main or secondary ring; p is annumber ranging from 0 to 4, p′ is an number ranging from 0 to 2 and p″is an number ranging from 0 to 3; wherein the main ring does not bearthe maximum number of substituents, each unsubstituted position bears anitrogen atom; LK is chosen from saturated and unsaturated, linear andbranched,-cyclic and non-cyclic, aromatic and non-aromatic, optionallysubstituted C₂-C₄₀ hydrocarbon-based chains, bearing at least onecationic charge, optionally interrupted with at least one hetero atom orgroup comprising at least one hetero atom; wherein LK may end with ahetero atom or group bearing at least one hetero atom if LK is linked toW′₂ or W′₅; and wherein LK may end with a group bearing at least onehetero atom chosen from —CO— and —SO₂— if LK is linked to W₆ or W₁, andat least one compartment comprising an oxidizing composition.